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IRRIGATION SCHEDULINGUsing

REAL TIME SOIL MOISTURE MEASUREMENTS

A report on methods and procedures used by the Bureau of Reclamation’sLower Colorado Region to provide field irrigation scheduling during the time

period from about 1975 to about 1990

December 2003

Preface

The Bureau of Reclamation’s Lower Colorado Region (LC Region) was a pioneer indeveloping the neutron moisture gauge and associated procedures for schedulingirrigations. This report describes the procedures developed initially by Dr. MelvinCampbell. Some of the techniques have since been refined through years of daily useof the gauge for production irrigation scheduling by Reclamation, district, Bureau ofIndian Affairs, and Tribal staff. Individuals most closely involved with developmentefforts have since transferred from the Lower Colorado Region or have retired. Therefore, resources of Reclamation’s Upper Colorado Region, headquartered in SaltLake City, Utah, have been used to prepare and produce this report. Three individualsclosely associated with development and use of the neutron moisture gauge havecontributed to the preparation of this report. They are: Stan Conway, Land Suitabilityand Water Quality Group, Technical Service Center, Denver, Colorado; Michael Stuver,Regional Water Management Coordinator, Upper Colorado Region, Salt Lake City,Utah; and Terry Taylor, Soil Scientist, Retired, Dillingham, Alaska. The report wascompiled by Michael Stuver with material and editing provided by Stan Conway andTerry Taylor. Completion of this report has been on a time-available basis and hasrequired several years to finish.

About This Report

This report describes how Reclamation provided field irrigation scheduling services in itsLower Colorado Region during the time period from about 1975 to about 1990. It maybe helpful to organizations desiring to provide a field irrigation scheduling service. Chapter 1 gives some general background information. Chapter 2 discusses the theoryand procedure used to schedule irrigations using in-place field moisture measurements. Chapter 3 describes the equipment used to conduct field irrigation scheduling programsin the LC Region. Chapter 4 discusses what is needed and describes how to begin afield irrigation scheduling service. Finally, Chapter 5 describes the day-to-day activitiesinvolved in providing a field irrigation scheduling service.

Table of Contents

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TABLE OF CONTENTS

1 - INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2 - THEORY OF SCHEDULING IRRIGATIONS USING MOISTURE GAUGES . . . . . . 4How Irrigation Scheduling Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4How Plant Stress is Determined . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3 - REQUIRED EQUIPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13The Neutron Measuring Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Description of Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Use of Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Standardization Barrels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Infrared Thermometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Description of Thermometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Use of Thermometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Soil Auger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Access Tubes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Access Tube Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4 - GETTING STARTED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Starting a New Field Irrigation Scheduling Service . . . . . . . . . . . . . . . . . . . . . . . 24

Calibrating Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Standardizing the Neutron Moisture Gauge . . . . . . . . . . . . . . . . . . . . . . . . 26Establishing Well-Watered Baseline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5 - SCHEDULING IRRIGATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Starting Irrigation Service to a New Field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Locating Access Tube Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Accessibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Irrigation Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Soil Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Crop Stand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Installing Access Tubes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32Determining Refill Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Using Optimum Moisture Content . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32Using Crop Water Stress Index (CWSI) . . . . . . . . . . . . . . . . . . . . . . . 33Using Observation of Visible Stress . . . . . . . . . . . . . . . . . . . . . . . . . . 33Using Farmer's Judgement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Establishing Full Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34Visiting Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35Contacting Farmers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Table of Contents

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LIST OF TABLES

Number Title Page

1 Terms and Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 Well-Watered Base Line Coefficients for Selected Crops . . . . . . . . . . . 12

LIST OF FIGURES

1 Graphical Scheduling with Neutron Probe Measurements . . . . . . . . . . . 52 CWSI vs. Date for Wheat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Typical Vapor Pressure Deficit vs Temperature

Depression Graph . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Foliage-Air Temperature vs. Vapor Pressure

Deficit for Well-Watered Alfalfa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 CPN Model 503 Moisture Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 Taking Moisture Readings With the 503 . . . . . . . . . . . . . . . . . . . . . . . . 157 Probe Rating Table - Uniform Count Increment . . . . . . . . . . . . . . . . . . 168 Probe Rating Table - Uniform Water Content Increment . . . . . . . . . . . . 17

9 Gauge on Standardization Barrel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 10 Infrared Thermometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 11 Measuring Turf Canopy Temperature with the Infrared Thermometer . 20 12 Sample Plant Foliage Temperature Data . . . . . . . . . . . . . . . . . . . . . . . 2213 Access Tube Cap Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2314 Installing a Steel Access Tube Using the Access Tube Driver . . . . . . . 2315 Soil Moisture in Inches per Foot vs. Count

Ratio of the Neutron Moisture Gauge . . . . . . . . . . . . . . . . . . . . . . . . 2716 Neutron Probe Standard Count Determination . . . . . . . . . . . . . . . . . . . 2917 Sample Printout from Program VEGY . . . . . . . . . . . . . . . . . . . . . . . . . . 3418 Data for CWSI Hand Calculation Example . . . . . . . . . . . . . . . . . . . . . . 3519 Hand Calculating Crop Water Stress Index . . . . . . . . . . . . . . . . . . . . . . 3620 Sample Field Graph . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3821 Sample Farmer Report Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4022 Sample Computer Generated Farm Irrigation Schedule . . . . . . . . . . . . 41

APPENDIX

A Relative Humidity, Percent - Centigrade TemperaturesB Vapor Pressure of Water Below 100 °CC Equipment Drawings and SpecificationsD Blank Field Data sheetsE Using Program VEGY

Chapter 1 - Introduction

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FIELD IRRIGATION SCHEDULING

1 - INTRODUCTION

The efficient use of water is necessary in many areas to meet existing needs. In someareas, extensive use of water for irrigation and the increasing need for municipal andindustrial water is depleting available supplies. In other areas there is an abundance ofwater. Yet, the high cost of fertilizers and farm labor or the need to improve crop yieldsand quality are causing the farmer to look for ways to improve on-farm irrigationefficiency.

The Bureau of Reclamation began its involvement with on-farm field irrigationscheduling when it began its Irrigation Management Service (IMS) in the early 1970's. IMS provided a staff of one or two specialists on-site to help local irrigation districtsestablish an IMS. The local irrigation district also provided one or more employees. Reclamation intended to withdraw its IMS staff when the district’s staff was fully trainedand capable of continuing the IMS on its own.

Reclamation’s Lower Colorado Region (LC Region) had been involved in the IMSprogram from the early 1970's to the early 1990's. The LC Region continued to providetechnical support for several years after it discontinued active participation in local IMSprograms. This report describes the process of scheduling irrigations using fieldmoisture measurements that was adopted by the LC Region. The standard device fortaking these measurements was the neutron moisture gauge.

This report is based upon the LC Region’s efforts to provide field irrigation schedulingservices. It is intended to be used by Federal and State agencies, irrigation districts, orprivate consultants that are supporting or providing an irrigation scheduling service. Itmay also be helpful to private farmers who purchase their own gauges and provide theirown scheduling service. The report discusses procedures for starting a new service. Also, it describes the necessary equipment and how to use the equipment. Finally, itdescribes the process for conducting field activities and communicating findings to thefarmer.

Improved on-farm efficiencies may require changes in present irrigation and waterdelivery practices. The irrigator may need better information to help him know when toirrigate a particular crop. Proper scheduling depends upon how much water is availableto the plant. It also depends upon how fast that plant or crop is using water. The farmermust also know how much water to apply. This depends upon the amount of waterused by the crop, the distribution uniformity (irrigation efficiency) of the irrigation system,the water holding capacity of the soil, and salt leaching requirements.

By using careful management and sound irrigation scheduling practices, the farmer canrealize the direct savings in water, fertilizer, pesticide, herbicide, and farm labor. Inaddition, many farms have seen increases in quality and quantity of their yields.


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Although irrigation scheduling helps the farmer, irrigation districts usually provide thescheduling service. Reclamation has, on occasion, also helped provide the service. Ina few instances, private consultants provide the service for a fee. Some large farmsbuy their own equipment and provide their own service. Unless a farm is large,however, most farmers cannot justify the cost of the equipment. In the LC Region,Reclamation partnered with local irrigation districts and a Native American Tribe toprovide the services.

Services provided by an irrigation district are usually more economical than similarservices provided by a farmer. When a district provides the service, it spreads the costof equipment among many individuals and can better control the quality and accuracy ofthe scheduling. Also, a district can better assess the success of its water managementactivities when the field irrigation scheduling service is a part of its water managementprogram.

Districts have met the cost of the service in several ways. Some included the fieldirrigation scheduling costs with other operating costs that are covered with a variety oftaxes and assessments. Other districts provided the service for a fee. Farmers paid afee based upon the number of acres or fields enrolled in the service. A fully equippeddistrict technician could easily serve several farms. Typically, a technician served about5,000 acres when 40-acre fields were the norm.

The LC Region started its Water Management and Conservation (WMC) program in1973. (In 1996, the WMC Program became officially known as the Water ConservationField Services Program (WCFSP) with little or no emphasis on providing field irrigationscheduling with the neutron moisture gauge.) This was about the same time theprogram was being introduced in other areas of the western United States. Theprogram was originally known as the Irrigation Management Service (IMS) and initiallyprovided field irrigation scheduling service to participating project water users.

The IMS used a computer model to schedule irrigations. The model utilized usedweather data to compute crop water use and a soil water budget to determine timingand amount of water to apply. The IMS computer programs were developed byReclamation's Technical Services Center (formerly known as the Engineering andResearch Center) staff for use on Reclamation's CYBER computer system. Participating projects accessed the CYBER with computer terminals and dedicatedtelephone lines. Eventually, the IMS service was expanded to provide a gravitydistribution scheduling program. As Reclamation's IMS program expanded andcontemplated providing additional services, the program was renamed the WaterManagement and Conservation Program.

The IMS Program was introduced simultaneously to three irrigation projects in theLC Region. These were:

(1) Wellton-Mohawk Irrigation District, near Wellton, Arizona; (2) Palo Verde Irrigation District, near Blythe, California; and (3) Colorado River Indian Irrigation Project, at Poston (near Parker),


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Arizona.

All three IMS programs began using the IMS computer programs with varying degreesof success. Three major problems became obvious. First, terminal connections withthe CYBER computer in Denver were unreliable. Second, the computer model wouldnot duplicate observed field conditions to an acceptable level of accuracy. Finally,farmers lacked confidence in the IMS schedules. Farmers' lack of confidence causedsome sponsoring districts to consider dropping the programs.

To improve reliability and acceptability of the IMS programs, Reclamation specialists inthe LC Region worked with a company that manufactured neutron moisture/densitygauges for the construction industry. Together, they developed a neutron moisturegauge suitable for measuring agricultural soil moisture content. Prototype models weredeveloped, tested in the field, and refined until models suitable for production fieldscheduling were available. Procedures were then developed and implemented forscheduling irrigations with the newly developed neutron moisture gauge (often calledthe neutron probe). Eventually, use of the IMS programs on the CYBER computer wasdiscontinued by the LC Region in favor of the more precise method of schedulingirrigations with the neutron moisture gauge.

The procedures and techniques described here have been used successfully by severalirrigation districts for over 25 years. Improvements and refinements have evolvedduring these years. Several types of non-nuclear moisture sensing devices are beingdeveloped and tested. Some of these devices may eventually replace the neutronmoisture gauge. However, this report does not address these latest developments.

Chapter 2 - Theory of Scheduling Irrigations Using Moisture Gauges

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2 - THEORY OF SCHEDULING IRRIGATIONS USING MOISTURE GAUGES

How Irrigation Scheduling Works

The neutron moisture gauge, commonly called a "neutron probe," is a practical tool formaking rapid and accurate measurements of soil moisture. This real time measurementof soil moisture makes possible quick and accurate determinations of the projectedirrigation dates and the amounts of water to apply and eliminates the need for extensivecomputations required to determine crop water use. This field irrigation schedulingprocess assumes the plant will use as much water from the soil as possible withoutimpairing crop production and causing water stress. When the soil moisture content(SMC) reaches a predetermined minimum allowable moisture content, the crop shouldbe irrigated. The irrigation scheduling procedures described below refer to the neutronmoisture gauge but are equally applicable to any soil moisture sensing device that canbe calibrated to indicate soil moisture content.

Gauge readings should be taken biweekly during the summer and weekly during thewinter if crops are grown throughout the year. This provides sufficient information todetermine the rate of moisture depletion in the soil. The readings can be plotted on afield graph. The amount of water required to refill the soil profile to field capacity can beaccurately determined. The next irrigation date can be predicted as much as a week inadvance. If a computer is available, it can use the gauge readings and compute thenext irrigation date automatically. (The IMS staff at Parker, AZ developed an IBM-compatible computer software package for MS-DOS that makes these computationsand print the reports.)

In graphical irrigation scheduling, the SMC is measured with a neutron moisture gaugeand the measurements are plotted on a graph. The x-axis on the graph represents thedates readings are taken. The y-axis represents the SMC in each foot of soil in theprofile where a reading is taken. Readings are usually taken from the first-foot, second-foot, and third-foot increments of the soil profile. In some deep-rooted, permanentcrops, readings may be taken as deep as 5 feet. The readings taken from the first ortop foot of the profile are used to determine the next irrigation date. Combined readingsfrom the entire profile are used to determine plant water consumption and the amount ofwater needed to replenish the root zone. The irrigation efficiency and the leachingrequirement are needed to adjust the irrigation amount.

Figure 1 shows a typical graph of plotted gauge readings. The minimum allowable SMCoccurring in the first foot of the profile is marked on the graph as a horizontal line. Thisis called the refill line or refill point. The refill line is shown as the dashed horizontal linein Figure 1.

At least two sets of gauge readings must be taken on different days to determine thenext irrigation date. If evapotranspiration rates are changing rapidly, additional readingswill be required. To determine the date, the first-foot SMC readings are plotted


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Figure 1 - Graphical Scheduling with the Neutron Probe


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the graph (see the 0" - 12" Depth portion of Figure 1). A line is drawn through the twopoints and extended downward to the horizontal refill line. The date on which theextended line intersects the refill line is the projected date of the next irrigation. In someinstances, only one reading will be available after an irrigation. However, the one reading can still be used to predict the next irrigation date, providedtwo or more readings were taken before the irrigation and the evapotranspiration rate isrelatively constant. A line having the same slope as the line through the prior readingscan be passed through the single point and extended downward to the refill line. Again,the date on which the line intersects the refill line is the projected date of the nextirrigation. This prediction will be refined with the next set of readings.

The amount of water used by the crop (includes evaporation) is the total of thedepletions in each foot of the profile. These are shown as A(1), A(2), and A(3) inFigure 1. The amount to apply is the total of A(1), A(2), and A(3) divided by theirrigation efficiency.

How Plant Stress is Determined

An essential element in the scheduling process is determining the minimum allowableSMC. One method for establishing the minimum allowable SMC is to identify the pointat which the plant is no longer adequately watered. A plant's temperature is directlyrelated to its transpiration rate. Under similar atmospheric conditions, a healthy,well-watered plant will be cooler than an unhealthy plant. There will be moreevaporative cooling at the leaf surface in the healthy case. It follows then that, bymeasuring the plant temperature and comparing it to the air temperature it is possible totell if the plant is under stress. Stress would be due to anything that would interfere withthe transpiration process: lack of soil moisture, insect infestations, and other causes. However, this discussion assumes that the cause of plant stress is due only to lack ofadequate soil moisture.

Plants that have been stressed require some time to recover after an irrigation. Thelength of this recovery period is influenced by several factors. These include the degreeof stress the plant has undergone, the species of the plant, its stage of growth, and itsroot depth. The more often the crop must recover from stress, the greater the impact tocrop production and yield. Thus, minimizing or eliminating water stress will improvecrop production and yield.

Figure 2 illustrates this stress recovery process. A wheat plot received an irrigation onday 100. This figure shows the changing Crop Water Stress Index (CWSI) during aportion of the growth period. The CWSI is a measure of water stress ranging from 0.0shortly after an irrigation to 1.0 at the wilting point.


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Figure 2CWSI vs. Day of Year for Wheat


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Beginning on day 72, the CWSI increased with time, reaching a value of +0.67 beforeirrigation. The CWSI did not drop to zero immediately after the irrigation but decreasedto a minimum on day 106. The 5 to 6 days required to reach the minimum arenecessary to allow the plant to recover from a stressed condition. Time is needed forthe water to move throughout the root zone and rehydrate the leaves. Roots, previouslyin dry soil, need time to grow new root hairs to extract soil water at a normal rate. Thus,too much water stress retards growth and reduces crop production.

Irrigating too frequently has the same impact on crop production and yield as stress. Roots are without air after each irrigation until the free water has drained from the soilprofile. During this time, plant growth and development nearly stops.

Research has shown that for any given crop, plant stress can be quantified using threeeasily measured parameters. These include the foliage temperature measured with theinfrared thermometer; air temperature; and vapor pressure deficit. The vapor pressuredeficit is commonly called the evaporative demand of the atmosphere. The vaporpressure deficit is calculated from dry- and wet-bulb air temperatures taken in the fieldat approximately the same time as the infrared thermometer readings. Figure 3 is agraphical representation of the relationship between the crop's foliage-air temperaturedifferential and the vapor pressure deficit of the atmosphere. The lower bound orbaseline represents the relationship for a healthy, actively transpiring, well-wateredcrop. The upper bound is the non-transpiring or wilted crop.

Some terms and definitions about the baselines used in calculating the CWSI areshown in Table 1.

From these baselines one is able to derive the CWSI. If the foliage-air temperaturedifferential for a given vapor pressure deficit falls on the lower baseline, such as at pointC on Figure 3, the crop is said to be non-stressed or well-watered (transpiring at thepotential rate). If the point is on the upper bound (point A), the crop is at maximumstress (non-transpiring or wilted). Any point between these limits (point B for instance)indicates that the plant is under some stress. As point B gets closer to point A, the levelof water stress increases. CWSI is defined as the distance ratio BC/AC.

The CWSI provides a measure of how the crop is responding to existing soil moistureconditions. A CWSI of near zero (0) indicates the crop is in a well watered condition. This well watered condition will continue for as long as the soil moisture can meet theplant's water needs. A CWSI of one (1) indicates insufficient soil moisture to sustainplant life. A CWSI value below 0.1 would probably not represent stress but could be afluctuation about the baseline. Research has shown that the critical CWSI, where cropproduction begins to falter is at 0.3 and 0.45 for wheat and cotton, respectively. Thus, asmall amount of stress is acceptable before irrigation becomes necessary. Research iscontinuing to determine the critical CWSI for other crops. Considerable data has beencollected to compute the slopes and intercepts defining the well watered baseline forseveral crops.


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Figure 3Typical Vapor Pressure vs. Temperature Depression Graph

Early in the growing season, infrared measurements may not represent true canopytemperatures. When there is incomplete canopy cover, the measurement with aninfrared thermometer from a distance of 30 to 45 feet results in an observed surfacetemperature that combines both foliage and soil temperatures. The resulting "canopy"temperature is usually higher than the true foliage temperature. The calculated CWSI isnot a true crop water stress index.

The baseline slope and intercept for any given crop are established by collecting datawhile the crop is in a non-stress state. This is usually 4 to 5 days after irrigation. Datacollection should be done at different times of the day. This gives a good spread of datapoints due to changes in temperature and humidity. A linear regression on these datapoints will give the slope and intercept for the well-watered baseline. An example ofdata collected on alfalfa is shown in Figure 4.


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Term

Crop-air temperature differential (Tc-Ta)

Definition

Crop canopy temperature as measured with theinfrared thermometer minus the ambient airtemperature (dry-bulb temperaturepsychrometer).

Vapor Pressure Deficit (VPD) Potential saturation vapor pressure at themeasured ambient air temperature minus thecalculated existing vapor pressure.

Upper Limit Potential saturation vapor pressure at themeasured ambient air temperature minus thecalculated existing vapor pressure. This is thecanopy-ambient air temperature at whichtranspiration has ceased.

Crop Water Stress Index A measure of plant moisture stress whichcannot be greater than one; calculated bythe following formula:

CWSI = B - C A - C

where A = upper limit (Tc-Ta)B = actual measured (Tc-Ta) C = value of Tc-Ta if crop were well-watered

Table 1Terms and Definitions

Suggested slopes and intercepts for several crops are shown in Table 2. These mayvary slightly according to region and climate.

Thus, the CWSI can be used to initially set the refill point. Using wheat as an example,the critical CWSI is about 0.3. Soil moisture reading are taken in the field at the sametime as when the CWSI is determined. When the CWSI reaches approximately 0.3, thecorresponding soil moisture reading in the first-foot interval is noted. This is themoisture reading that will be plotted as the refill line on the field graph.


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Figure 4Foliage-air Temperature vs. Air Vapor Pressure Deficit for Well-watered Alfalfa

Grown at a Variety of Specified Sites and Dates During 1980


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))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))Common Name Scientific Name Conditions Intercept Slope)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))

Alfalfa Medicago sativa L. Sunlit 0.51 -1.92

Barley Hordeum vulgare L. Sunlit, Pre-heading 2.01 -2.25Sunlit, Post-heading 1.72 -1.23

Bean Phaseolus vulgaris L. Sunlit 2.91 -2.35Shaded -1.57 -2.11

Beet Beta vulgaris L. Sunlit 5.16 -2.30

Chard Beta vulgaris L. Sunlit 2.46 -1.88

Corn Zea mays L. Sunlit, no tassels 3.11 -1.97

Cotton Gossypium hirsutum L. Sunlit 2.00 -2.24

Cowpea Vigna catjang Walp. Sunlit 1.32 -1.84

Cucumber Cucumis sativus L. Sunlit 4.88 -2.52Shaded -1.28 -2.14

Fig tree Ficus carica L. Sunlit 4.22 -1.77

Guayule Parthenium argentatum Sunlit 1.87 -1.75

Kohlrabi Brassica oleraceacaulorapa communis DC. Sunlit 2.01 -2.17

Lettuce, Leaf Lactuca scariola L. Sunlit 4.18 -2.96

Pea Pism sativam L. Sunlit 2.74 -2.13

Potato Solanum tuberosum L. Sunlit 1.17 -1.83

Pumpkin Cucurbita pepo L. Sunlit 0.95 -1.93Shaded -1.32 -2.10

Rutabaga Brassica napo-brassica Sunlit 3.75 -2.66

Soybean Glycine max L. Merr. Sunlit 1.44 -1.34

Squash, Curbita pepo L. Sunlit 6.91 -3.09 Hubbard Shaded 2.12 -2.38

Squash, Zucchini Cucurbita pepo L. Sunlit 2.00 -1.88

Sugar Beet Beta vulgaris L. Sunlit 2.50 -1.92

Sunflower Helianthus annuus L. Sunlit 2.86 -1.96

Tomato, Mill. Lycopersicum esculentum Sunlit 2.86 -1.96

Turnip Brassica rapa L. Sunlit 1.94 -2.26

Wheat, Podura Triticum durum Desf. Sunlit, pre-heading 3.38 -3.25Shaded, post-heading 2.88 -2.11

Table 2. Well-Watered Base Line Coefficientsfor Selected Crops

Chapter 3 - Required Equipment

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3 - REQUIRED EQUIPMENT

Only a limited amount of equipment is needed to provide irrigation scheduling servicesto local farmers. The following section describes the equipment used by the LC Regionand suggests proper usage procedures.

In addition to normal office space, vehicle, and miscellaneous hand tools, specializedequipment include:

(1) Neutron moisture gauge(2) Infrared thermometer(3) Standardization barrels(4) 2-inch diameter soil auger (preferably power driven)(5) Access tubes w/bottom seal and caps (steel or aluminum are preferred)(6) Access tube driver

The following sections describe the specialized equipment:

The Neutron Measuring Gauge

Description of Gauge

The gauge is the instrument used to measure the moisture in the soil. It isportable and can be carried from field to field. However, an access tube must beinstalled wherever a measurement is to be made.

The gauge uses a high energy source to detect the presence of hydrogen atomsin the soil. When the high energy source of the gauge is lowered into the access tube,fast neutrons are emitted. Neutron emission occurs when an alpha particle emitter(americium) is mixed with beryllium powder in a tightly compressed pellet. Fastneutrons ricochet strongly from large atoms like a golf ball does when it collides with abowling ball. Very little energy is lost. Neutrons are dramatically slowed down,however, if they collide with hydrogen atoms. Since the hydrogen atoms are the samemass as the neutron, the neutrons lose energy. The detector tube of the moisturegauge can then count the slow moving neutrons as they pass through the tube.

In most soils the major source of hydrogen is water; hence, the only majormoderator of fast neutrons would be water. Therefore, when a soil has a high moisturecontent (such as at field capacity), the gauge readings would be high. On the otherhand, soils that are dry or are approaching the wilting point would show low readings. Thus, a relationship can be established between the gauge counts and the amount ofwater in the soil.

Several gauges are on the market now. However, primary experience in the LCRegion has been with the Campbell Pacific Nuclear 503 Moisture Gauge (503 gauge).


14

Figure 5CPN Model 503 Moisture Gauge

If other makes of gauges are in use, consult the owner's manual for a completedescription and operating instructions.

Two models of the 503 gauge have been used. The Standard 503 gauge (S-503)displays raw counts that must be converted to the desired units of measure. The DirectReadout 503 gauge (DR-503) contains a microprocessor that converts raw counts toany of several desired units of measure.

The primary parts of the 503 gauge are: Thecase, the display, and the probe containing theradioactive source and detector electronics. Thecase is a rectangular box approximately 7 inches (18cm) square by 14 inches (36 cm) length. A tube forholding the probe is located in the center of the case. The readout display is attached to one side. Thelower portion of the case is a neutron shield filledwith a high hydrocarbon paraffin-based wax. Thewax will partially absorb the neutrons emitting fromthe source. This also helps shield the user fromstray neutron radiation. Figure 5 is a manufacturer'sphoto showing gauge with the probe locked in itshousing. In this configuration, the gauge is ready tobe carried into the field.

The display unit is contained in a 7-inch by 7-inch by 2-inch box. The display unit contains thedisplay circuitry, the battery pack, and a liquid crystaldisplay (LCD) or light emitting diode readout. Theback of the display has a fuse holder and the cableattachment block.

The probe unit has four main parts: theexternal stainless steel case, the radioactive sourcepermanently secured in the lower part of the probetube, the neutron detector tube, and the detectorelectronics. The probe, containing the radioactive source and display electronics, isattached to the display by a cable.

A cable is used to lower the probe tube into the access tube and to transmitelectrical pulses to the display unit. Cable stops are placed on the cable to permitlowering the probe to predetermined depths in the access tubes. The setting of thecable stops depends upon the adaptor used to support the gauge on top of the accesstubes. Specifications for the adaptor used in the LC Region are shown in Appendix C.

With this particular adaptor, the first cable stop should be 26 inches (66 cm) fromthe bottom of the detector tube to the base of the first stop. All additional stops are set


15

Figure 6Taking Moisture readings with the 503.

in increments of 12 inches (30.5 cm) from the base of the first cable stop. The stopplacement should be checked weekly because the insulation on the cable stretches andslides over time. Heat and rough handling accelerate this process. Changes in stopplacement may cause inconsistent readings.

Use of Gauge

Soil moisture measurements are taken by placing the gauge on top of the accesstube and lowering the probe to the desired depth. Figure 6 shows the gauge positionedon the access tube to take readings. Readings are taken by pressing START, andrecording the displayed number in the field book. The normal sampling time is 30seconds for the S-503 and 16 seconds for the DR-503. Therefore, the numbers will notbe displayed immediately after START has been pressed. (Consult the operator'smanual if other intervals are desired.) The S-503 displays raw counts that must beconverted to moisture content using a rating table similar to the tables shown inFigures 7 and 8. The DR-503 displays the moisture content in several preselected unitsof measure. The normal unit of measure used in the United States for agriculturalapplications is inches of water per foot of soil depth (in/ft).

The DR-503 can directly display the moisture content and store readings as theyare taken in the field. Some additional steps are needed to initialize the gauge beforetaking field measurements. Place the gauge on the shipping case with the probe tubein the retracted position. Press the key marked UNITS. If the LCD does not display IF(in/ft), press the STEP key until IF is displayed. When IF is displayed, press the ENTERkey to record desired unit of measure. Now press the key marked TIME. Press theSTEP key until 16 seconds appears. Press the ENTER key to record desired samplinginterval.

Next take a new standard count. Press the key marked STD. The probewill display the old standard count if onehas been recorded. A new 32-countstandard will be taken automaticallywhen the START key is pressed. Bepatient, this will take several minutes. When the 32-count standard has beentaken, make a note of the new standardcount displayed. Press the STEP keyand this will display the previousstandard count. Press the STEP keyagain and the Chi value will bedisplayed. The Chi value is thestandard deviation of the 32 countsdivided by the square root of the 32-count average. This value should be


16

WATER CONT, IN/FT 06/25/92 PROBE NO 1 (SN=4503) --------------------------------------------------------------- 1000'S HUNDREDS 0 100 200 300 400 500 600 700 800 900 --------------------------------------------------------------- 6| 0.40 0.41 0.42 0.43 0.44 0.46 0.47 0.48 0.49 0.50 7| 0.51 0.52 0.53 0.54 0.55 0.57 0.58 0.59 0.60 0.61 8| 0.62 0.63 0.64 0.65 0.67 0.68 0.69 0.70 0.71 0.72 9| 0.73 0.74 0.75 0.77 0.78 0.79 0.80 0.81 0.82 0.83 10| 0.84 0.85 0.86 0.88 0.89 0.90 0.91 0.92 0.93 0.94 11| 0.95 0.96 0.98 0.99 1.00 1.01 1.02 1.03 1.04 1.05 12| 1.06 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 13| 1.17 1.19 1.20 1.21 1.22 1.23 1.24 1.25 1.26 1.27 14| 1.29 1.30 1.31 1.32 1.33 1.34 1.35 1.36 1.37 1.39 15| 1.40 1.41 1.42 1.43 1.44 1.45 1.46 1.47 1.48 1.50 16| 1.51 1.52 1.53 1.54 1.55 1.56 1.57 1.58 1.60 1.61 17| 1.62 1.63 1.64 1.65 1.66 1.67 1.68 1.70 1.71 1.72 18| 1.73 1.74 1.75 1.76 1.77 1.78 1.79 1.81 1.82 1.83 19| 1.84 1.85 1.86 1.87 1.88 1.89 1.91 1.92 1.93 1.94 20| 1.95 1.96 1.97 1.98 1.99 2.01 2.02 2.03 2.04 2.05 21| 2.06 2.07 2.08 2.09 2.10 2.12 2.13 2.14 2.15 2.16 22| 2.17 2.18 2.19 2.20 2.22 2.23 2.24 2.25 2.26 2.27 23| 2.28 2.29 2.30 2.31 2.33 2.34 2.35 2.36 2.37 2.38 24| 2.39 2.40 2.41 2.43 2.44 2.45 2.46 2.47 2.48 2.49 25| 2.50 2.51 2.53 2.54 2.55 2.56 2.57 2.58 2.59 2.60 26| 2.61 2.62 2.64 2.65 2.66 2.67 2.68 2.69 2.70 2.71 27| 2.72 2.74 2.75 2.76 2.77 2.78 2.79 2.80 2.81 2.82 28| 2.84 2.85 2.86 2.87 2.88 2.89 2.90 2.91 2.92 2.93 29| 2.95 2.96 2.97 2.98 2.99 3.00 3.01 3.02 3.03 3.05 30| 3.06 3.07 3.08 3.09 3.10 3.11 3.12 3.13 3.15 3.16 31| 3.17 3.18 3.19 3.20 3.21 3.22 3.23 3.24 3.26 3.27 32| 3.28 3.29 3.30 3.31 3.32 3.33 3.34 3.36 3.37 3.38 33| 3.39 3.40 3.41 3.42 3.43 3.44 3.46 3.47 3.48 3.49 34| 3.50 3.51 3.52 3.53 3.54 3.55 3.57 3.58 3.59 3.60 35| 3.61 3.62 3.63 3.64 3.65 3.67 3.68 3.69 3.70 3.71 36| 3.72 3.73 3.74 3.75 3.76 3.78 3.79 3.80 3.81 3.82 37| 3.83 3.84 3.85 3.86 3.88 3.89 3.90 3.91 3.92 3.93 38| 3.94 3.95 3.96 3.98 3.99 4.00 4.01 4.02 4.03 4.04 39| 4.05 4.06 4.07 4.09 4.10 4.11 4.12 4.13 4.14 4.15 40| 4.16 4.17 4.19 4.20 4.21 4.22 4.23 4.24 4.25 4.26 41| 4.27 4.29 4.30 4.31 4.32 4.33 4.34 4.35 4.36 4.37 42| 4.38 4.40 4.41 4.42 4.43 4.44 4.45 4.46 4.47 4.48 43| 4.50 4.51 4.52 4.53 4.54 4.55 4.56 4.57 4.58 4.60 44| 4.61 4.62 4.63 4.64 4.65 4.66 4.67 4.68 4.69 4.71 45| 4.72 4.73 4.74 4.75 4.76 4.77 4.78 4.79 4.81 4.82 46| 4.83 4.84 4.85 4.86 4.87 4.88 4.89 4.91 4.92 4.93 47| 4.94 4.95 4.96 4.97 4.98 4.99 5.00 5.02 5.03 5.04 48| 5.05 5.06 5.07 5.08 5.09 5.10 5.12 5.13 5.14 5.15 49| 5.16 5.17 5.18 5.19 5.20 5.22 5.23 5.24 5.25 5.26 50| 5.27 5.28 5.29 5.30 5.31 5.33 5.34 5.35 5.36 5.37 COUNT INTERVAL = 0.001 IN/FT PER 10 COUNTS EQUATION: W=0.0001107 x C -.264

Figure 7Probe Rating Table - Uniform Count Increment


17

COUNT INCHES

3037 = .50 3227 = .55 3417 = .60 3606 = .65 3796 = .70 3986 = .75 4176 = .80 4366 = .85 4555 = .90 4745 = .95 4935 = 1.00 5125 = 1.05 5315 = 1.10 5505 = 1.15 5694 = 1.20 5884 = 1.25 6074 = 1.30 6264 = 1.35 6454 = 1.40 6643 = 1.45 7023 = 1.55 7213 = 1.60 7403 = 1.65 7592 = 1.70 7782 = 1.75 7972 = 1.80 8162 = 1.85 8352 = 1.90 8541 = 1.95 8731 = 2.00 8921 = 2.05 9111 = 2.10 9301 = 2.15 9491 = 2.20 9680 = 2.25 9870 = 2.3010060 = 2.3510250 = 2.4010440 = 2.4510629 = 2.50

COUNT INCHES

10819 = 2.5511009 = 2.6011199 = 2.6511389 = 2.7011578 = 2.7511768 = 2.8011958 = 2.8512148 = 2.9012338 = 2.9512528 = 3.0012717 = 3.0512907 = 3.1013097 = 3.1513287 = 3.2013477 = 3.2513666 = 3.3013856 = 3.3514046 = 3.4014236 = 3.4514615 = 3.5514805 = 3.6014995 = 3.6515185 = 3.7015375 = 3.7515564 = 3.8015754 = 3.8515944 = 3.9016134 = 3.9516324 = 4.0016514 = 4.0516703 = 4.1016893 = 4.1517083 = 4.2017273 = 4.2517463 = 4.3017652 = 4.3517842 = 4.4018032 = 4.4518222 = 4.5018412 = 4.55

COUNT INCHES

18601 = 4.6018791 = 4.6518981 = 4.7019171 = 4.7519361 = 4.8019551 = 4.8519740 = 4.9019930 = 4.9520120 = 5.0020310 = 5.0520500 = 5.1020689 = 5.1520879 = 5.2021069 = 2.2521259 = 5.3021449 = 5.3521638 = 5.4021828 = 5.4522208 = 5.5522398 = 5.6022588 = 5.6522777 = 5.7022967 = 5.7523157 = 5.8023347 = 5.8523537 = 5.9023726 = 5.9523916 = 6.0024106 = 6.0524296 = 6.1024486 = 6.1524675 = 6.2024865 = 6.2525055 = 6.3025245 = 6.3525435 = 6.4025624 = 6.4525814 = 6.50

Figure 8. Probe Rating TableUniform Moisture Content Increment


18

between 0.75 and 1.25. If the Chi value is within these limits, press the ENTER key andthe new standard count will be entered into the probe. If the Chi value is out of range,press the CLEAR key, and initiate the standard count procedure again. If the Chi valueis still out of range after the third try, the probe will require servicing.

If site locations and readings are to be stored in the gauge's memory, the memoryarea must be formatted. To do this, press the FMT key. The gauge will display K Data1. Key in a 1 if the gauge does not display a 1. Press the ENTER key. The gauge willdisplay Depths. The gauge can record up to 15 depths but measurements are normallytaken at three depths per tube site. However, the gauge will expect the same numberof depths at each site. When the number of depths is keyed in, press the ENTER key. The gauge will store the number of depths to be read and will display Set FMT?. Pressthe ENTER key and the gauge should display Ready. To clear all stored gaugereadings, press the FMT key; then press ENTER until Ready appears in the display.

The following procedure should be used when storing readings in the DR-503memory. Place the gauge on the access tube. Press LOG, key in the farm number,and press ENTER. Key in the field number and press ENTER. M3 will be displayed. Lower the probe to the first cable stop and press START. In about 16 seconds themeasurement is displayed. Press ENTER to store the measurement if themeasurement appears correct. Otherwise, press START and repeat the reading. M2will then be displayed after the gauge has stored the reading. Lower the probe to thenext stops repeating the START and ENTER sequence at each stop. Three readingsmust be recorded for each site. If readings are to be taken at only two depths, key in 0,and press ENTER in place of the third reading. After the third reading has beenentered, the total moisture will be displayed. Press ENTER if correct. The gauge willthen display IS DATA OK?. Press ENTER to store all data for the site. The gauge isnow ready to take readings at the next site.

The above procedures assume that the gauge has been properlystandardized. (See "Standardizing Gauge.")

Standardization Barrels

Standardization barrels are used to verify correct calibration of each gauge and toinsure that all gauges are calibrated to the same standard. Some gauges changecalibration gradually from season to season, especially in hot climates. The set ofstandardization barrels consists of two, large 30- or 55-gallon barrels. One is filled withair-dried sand and the other with saturated sand. The air-dry sand approximates thelower limit of the moisture contents encountered in the field and the saturated sandapproximates the upper limit. Local soils with high silt and clay contents may be used inplace of saturated sand. These soils should be near field-capacity when used.

Both barrels are fitted with access tubes centered in the barrels. The accesstubes should be of the same material as the access tubes used in the field. Each tubeextends far enough above the top of the barrel so the probe detector tube will be


19

Figure 9Gauge On Standardization Barrel

Figure 10Infrared Thermometer

suspended in the center of barrel when hanging on the second cable stop. Figure 9shows a moisture gauge set up on a standardization barrel ready to take ameasurement.

Be careful when placing sand in the barrels sothat the sand is adequately compacted to eliminatefuture settling. The barrels should be filled withsand to within 1-inch of the top. Water is added tothe sand in one barrel until the sand is saturatedand water stands freely above the sand. A lid witha 2-3/16-inch diameter hole to accommodate theaccess tube is placed on the top of each barrel. The lid should be sealed on the dry barrel withsilicone or rubber adhesive sealant as soon as thesand has been compacted. The lid is not sealed onthe wet barrel. An inspection hole could beprovided to facilitate maintaining the water at aconstant level above the sand. Otherwise, providean external filling tube as shown in Figure 9.

The apparent moisture content of each barrelis measured with a gauge accurately calibrated tolocal soil conditions. Twenty moisturemeasurements are taken and averaged todetermine the apparent moisture content of eachbarrel. Outside influences can affect gaugereadings, especially the dry barrel readings. Thiscan be minimized by maintaining the barrels andsurrounding area in a constant configuration.

Alternately, sand samples can be taken fromeach barrel. The samples should be analyzed inthe laboratory to determine actual moisture contentof each barrel.

Infrared Thermometer

Description of Thermometer

Soil water content can be inferred from tensiometers ormeasured with the neutron moisture gauge, but just knowinghow much water is in the soil is not enough. One must alsoknow the minimum amount of water that must remain in the soilwithout reducing crop production. The infrared thermometer(Figure 10) provides a means of determining the degree of cropwater stress by measuring crop foliage temperature. The


20

Figure 11Measuring canopy temperaturewith an infrared thermometer.

complete infrared thermometer includes a Bendix psychrometer for measuring wet anddry-bulb temperatures. The kit also contains a reference temperature black body forcalibrating the infrared thermometer. Newer models of the infrared thermometers havethe necessary built-in sensors and microprocessor to determine the CWSI directly.

Use of Thermometer

Crop foliage temperatures (and associated relative humidity) are measured todevelop the well-watered baseline curves and to determine plant water stressconditions. The infrared thermometer measures the temperature of the crop foliage,while the Bendix psychrometer measures wet-bulb and dry-bulb temperatures neededto determine relative humidity.

Data for the well-watered baseline may be collected anytime from about 9 a.m. to3 p.m. When using the infrared thermometer for detecting stress, readings arepreferably taken between noon and 2 p.m., when the sun is usually higher overhead. During these hours, shadows are the smallest and transpiration is at its peak. It is moreeffective to read each field at approximately the same time each day when checking forstress.

The temperature readings should all be takenin an area of the field where the largest percentageof the whole field will be represented. Readingsshould be taken approximately 50 feet into the fieldso temperatures will not be influenced by the edgeeffect of the field. Edges of the field may notreceive as much water or may be dried out faster bywinds. Taking temperatures from eight directions isnecessary to give a good average of the canopy orfoliage temperature. Figure 11 illustrates theprocedure for measuring canopy temperatures withan infrared thermometer.

The wet-bulb and dry-bulb temperaturesshould be taken as soon as possible after taking the infrared thermometer readings. First, apply distilled water to the sock of the wet-bulb. Be careful not to get water in thefan mechanism. Shake off the excess, then turn on the fan. Hold the psychrometerapproximately 1 meter from the ground and upwind from body temperature influences. The wet-bulb reaches its lowest temperature in 1 minute or less. Read both the wet-and dry-bulb temperatures together. Newer versions of the infrared thermometercompute and display the vapor pressure deficit and the crop temperature differentialdirectly. In this case, a psychrometer is not necessary to determine wet-bulb and dry-bulb temperatures.

Data collected at any given site should be recorded on a form similar to the one inFigure 12. The top half of this form contains information regarding the site and data


21

quality. Data quality refers to the existing climatic conditions when the data is taken andshould either be a 1, 2, or 3. If sunny, with light winds, data quality is 1 for GOOD. Ifslight overcast or just windy, data quality is 2 for FAIR. If cloudy or high winds, readingsprobably should not be taken, but the data quality is 3 for POOR. Be sure to enter thecrop name to the top right of TEMPERATURE MEASUREMENTS. Under the headingTEMPERATURE MEASUREMENTS, fill in the time of the readings and the fieldnumber or other reference to the area where readings are taken. Then record the dry-bulb, wet-bulb, and eight infrared thermometer readings.

Periodic checks should be made with the infrared thermometer against acalibration source or black body to see that it is reading correctly. Normally, the Bendixpsychrometer need only be watched for loss of power due to low batteries. Fluctuatingfan speeds, due to low batteries, cause the wet-bulb temperature to descend slowly andresult in inaccurate or variable readings.

Soil Auger

A 2-inch diameter soil auger is needed to bore holes to permit the installation ofaccess tubes. Any type of auger capable of boring a 2-inch diameter hole deep enoughto accept the longest access tube in use is acceptable. However, a power-driven,continuous-flite auger is preferred. The power-driven auger drills holes much faster andspeeds installation of access tubes. However, extra care must be taken to ensure thatthe auger does not over-bore the hole diameter.

Access Tubes

Probe access tubes must be installed at each location where soil moisturemeasurements will be taken. These tubes may be steel, aluminum, or PVC pipe for thenuclear gauge. Steel tubes are preferred because of better durability and lower cost.

The steel access tubes are 2-inch (50 cm) inside diameter, thin walled, rigid steelconduit. The conduit is purchased in 10-foot sections and then cut to the desiredlength. The tube is sealed on the bottom with a 1f-inch chain link fence post cap andwater repellent adhesive. The top is covered with a removable cap to protect the tubeand to keep out irrigation water and debris. The cap consists of a 2½- by 2½- by ¼-inchsteel plate bolted on top of a No. 11 rubber stopper. The cap should be painted with ahighly visible color of paint for ease in locating the tube. If a tube cannot be located ina field, the steel plate on the cap helps a good metal detector locate the tube. Figure 13shows a typical cap assembly.


22

PLANT FOLIAGE TEMPERATURE DATA SHEET

LOCATION Double Bar Ranch

YEAR DAY - DATE 4/22/95 BY LM DATA QUALITY 1

INSTRUMENT

MODEL No. - SERIAL No. -

CALIBRATION CHECK:

TIME INST. REF.

1400 24.6 24.6

WEATHER CLOUD CLOUD WIND WIND SUN X HAZE - TYPE - COVER - SPEED 4 DIRECTION SE

PRECIP. IRRIGATION Field S10 4/18

COMMENTS: Plants are in the milky dough stage

TEMPERATURE MEASUREMENTS CROP

SITE TIME FLDDRYBULB

WETBULB

DIRECTION OF VIEW

N NE E SE S SW W NW

1 1410 S10 24.7 15.0 23.5 23.7 23.7 23.4 23.6 23.2 23.2 22.8

2

3

4

5

6

7

Figure 12Sample Plant Foliage Temperature Data


23

Figure 13. Access Tube Cap Assembly

Figure 14. Access Tube Driver

The length of the access tube isdetermined by the root structure of thecrop being scheduled. For most fieldcrops, a 44-inch (112 cm) tube will belong enough. It will permit readings downto 3 feet and provide extra clearancebelow the probe. This tube length isadequate for crops like cereal grains,alfalfa, cotton, and most vegetables.

A longer tube is preferred for citrus,grapes, dates, and other tree crops. Also, the longer tube will allow earlyidentification of water table problems.

Tube installation requires drilling a 2-inch diameter hose several inches deeperthat the tube length. The extra depth accommodates some soil sloughing that usuallyoccurs when the tube is driven into the hole.

Access Tube Driver

A specially designed driver is used to install steel accesstubes in holes that have been previously bored in the ground. The driver consists of a drop-hammer, guide rod, and anvil. The anvil is specifically designed to protect the top of the tubeand prevent tube deformation during the driving process. Theguide rod is attached to the anvil to center the force of thedrop-hammer.

In operation, the driver works much like a steel fence-post driver. The anvil is inserted in the top of the tube. Thedrop-hammer is repeatedly raised to the top of the guide rodand released. The force of the falling drop-hammer drives thetube into the ground. Figure 14 shows a photograph of anaccess tube driver.

PVC access tubes do not require a specially designeddriver. A hard rubber mallet is adequate for driving theseaccess tubes.

Chapter 4 - Getting Started

24

4 - GETTING STARTED

The LC Region started its field irrigation scheduling services on a demonstration basisat the two previously mentioned irrigation districts and on the Native American IndianReservation. The initial staff provided at each site consisted of a hydraulic engineer anda soil scientist provided by Reclamation and a soil scientist or soil conservationistprovided by the partner. The partners provided office space for each team. Reclamation provided furniture, equipment, and supplies. Reclamation and the partnersprovided vehicles for their own employees. As the programs expanded beyond theinitial acreage enrollment, the partners provided additional field technicians. Theultimate intent was to withdraw Reclamation employees after 3 to 5 years when thepartners could sustain the programs on their own. Lessons learned and insight gainedby Reclamation through these demonstration activities have resulted in the followingsuggestions for starting a new field irrigation scheduling service.

Starting a New Field Irrigation Scheduling Service

Starting a new field irrigation scheduling service involves several activities. Theseinclude recruiting field technicians; obtaining office space, equipment, and vehicles;preparing the equipment; and enrolling participating farmers.

Local procedures will govern the recruiting of field technicians. However, thetechnicians should have some knowledge of irrigated agriculture. They also shouldhave the skills to use the specialized equipment used for irrigation scheduling. Finally,they should be able to communicate effectively with the farmers.

Similarly, local conditions will govern the availability of office and work space. Theneutron moisture gauge will require special provisions for licensing, storage, andtransportation. The technicians also must be trained and certified by a qualifiedRadiation Safety Officer.

Local policies will determine how participating farmers will be recruited and enrolled. Enrollment should be open to all local farmers. However, program success is thegreatest when first consideration is given to the most progressive and cooperativefarmers. Experience has also demonstrated that the program is the most successfulwhen all of a participating farmer's fields are receiving scheduling services. Farmerscannot assess the benefits of the service fully when just a few "demonstration" fields arereceiving the service. The farmer must still schedule the irrigations on the non-enrolledfields. The demonstration fields are just considered a curiosity.

Compliance with regulations governing the possession and use of neutron moisturegauges is essential. The use of these gauges is regulated by Federal or State agenciesbecause the devices contain radioactive sources. Federal agencies usually are underthe jurisdiction of the Nuclear Regulatory Commission (NRC). Irrigation districts andprivate owners are under the jurisdiction of the State regulatory agency.


25

The owner must first obtain a license from the NRC and/or appropriate State agencybefore purchasing and taking delivery of nuclear moisture gauges. To get a license, theowner must meet conditions for storage and use of the nuclear gauge as set by either astate or federal regulatory agency. The owner should consult with the appropriateregulatory agency for specific requirements. Typically, the storage area must be aspecified distance away from areas frequented by people and animals. It must alwaysbe locked and must be properly marked. Again, all operators must be trained andcertified by a certified training instructor. Each person operating or servicing the gaugesmust be supplied with a dosimeter film badge to monitor radiation exposure. Thesebadges must be replaced and analyzed periodically. Finally, a record keeping systemmust be set up to maintain film badge and leak test reports and other correspondence. The NRC and/or State agency will periodically inspect the site to insure that the ownersand operators are in compliance with the regulations. The inspection includes anexamination of the record keeping system. Finally, Department of Transportationguidelines must be observed when the nuclear gauge is transported.

The remainder of the discussion on getting the service started concentrates on settingup the equipment and compiling the necessary information needed to operate theservice.

Calibrating Gauge

The neutron moisture gauges must be initially calibrated so the readings (counts)can be related to actual soil moisture. Soils have different chemical and physicalproperties that may affect the gauge readings. Calibration curves should be developedfor local conditions. The gauge, thus calibrated, can be used to measure the equivalentmoisture content of the standardization barrels.

To calibrate the gauge, select representative sites of the soils in the area to bemonitored. As the access tube hole is being bored, take soil samples at differentdepths. Use a soil sampler capable of taking a sample of a known volume. Seal thesamples in cans for later moisture determination in the laboratory. After installing theaccess tube, take gauge readings at the same depths where the samples were takenand record the measurements. Enough sites should be selected to give readings for arange of different moisture levels (wet, moist, and dry). The soil samples taken duringaccess tube installation are analyzed in the laboratory to determine the amount ofmoisture contained in the different soils.

A graph is prepared with the gauge readings on one axis. The moisture content ofthe soil, as determined in the laboratory, is on the other. The curves are thendeveloped and plotted on a graph similar to Figure 15. A straight line is then fitted tothe plotted points and the coefficients of the line are determined. A graph or table isthen prepared which relates the amount of moisture in the soil to a given gauge reading. This table also can be developed on the computer. The coefficients of the line also maybe entered into the gauge if the gauge is capable of displaying readings in actualmoisture content.


26

Some people contend that a calibration curve must be developed for each soiltype to be monitored. This is true if detailed research is involved. However, for thepractical use of the gauge for predicting and scheduling irrigations, experience showsthat one calibration curve is normally sufficient. There may be some instances whentwo curves are necessary, due to an extreme difference in local soil types.

Standardizing the Neutron Moisture Gauge

Ideally, the calibration procedure described above should be repeated each time anew gauge is put in service. The process also should be repeated at frequent intervalsto insure continued accurate operation of each gauge. Unfortunately, the process isvery time consuming.

An alternate procedure involves the use of standardization barrels. These barrelswere previously described in the "Required Equipment" chapter. The barrels withknown moisture content simulate typical "wet" and "dry" conditions in the field. Calibration curves are developed using gauge readings from the two barrels. Thisreplaces the process of taking readings in the field and determining the soil moisture inthe laboratory.

Standardization procedures are somewhat different for the S-503 and the DR-503gauges. Coefficients for the calibration curve must be computed manually for the S-503. Coefficients are computed automatically by the DR-503.

To standardize the S-503, take sets of 20 measurements with the probe loweredto the center each the barrel. For each set, the readings (counts) are recorded in anotebook, totaled, and averaged. The standard deviation is also computed.

The calibration equation is of the form: M=aC+b

where: M= Moisture content in inches of water per foot of soil depthC= Counts shown on displaya= Slope coefficientb= Intercept coefficient

and: a= (Mw - MD) and b= Mw - aCw (Cw - CD)

where: Mw= Moisture content of wet barrel (in/ft)Cw= Average for 20 readings on wet barrels (counts)MD= Moisture Content of Dry barrel (in/ft)CD= Average for 20 readings on Dry barrel (counts).


27

Figu

re 1

5. S

oil M

oist

ure

in In

ches

per

Foo

t of D

epth

vs.

Cou

nt R

atio

of t

he N

eutro

n M

oist

ure

Gau

ge

Coefficients "a" and "b" are used in the calibration equation to develop ratingtables used by field personnel to convert displayed counts to equivalent moisture


28

contents. Samples of two typical rating tables were previously shown in Figures 7 and8.

Data recorded during the standardization process also can be used to verifyproper operation of the gauge. No more than 6 of the 20 readings should be outside theacceptable range. The acceptable range is plus or minus the square root of theaverage count above and below the average count. The Chi value obtained by dividingthe square root of the average count by the standard deviation should be between 0.75and 1.25 (see Figure 16). If either of the above tests fail, additional sets of 20 readingsshould be taken on the appropriate barrel. Several additional failures indicate thegauge is defective and should be repaired.

To standardize the DR-503, place the gauge on the wet barrel and lower theprobe to the center of the barrel. Press the key marked CALIB and the gauge willdisplay Cal 1 IF. This is the first of eight calibrations that can be stored in the gauge. Only one calibration is needed for most agricultural soils. Now press the ENTER key. The gauge will display COEFFS?. Press the STEP key until SLFCAL is displayed. Press the ENTER key. The gauge will display M2 0.0--- and will wait for entry of themoisture equivalent of the wet barrel (inches of moisture per foot of soil). Key in wetbarrel moisture content and press the ENTER key. The gauge will display C 2 0---. (Itis waiting for entry of the average count for the wet barrel.) Press the START key andthe gauge will determine the average count for the wet barrel. The gauge will takeabout 4 minutes to complete the measurement. When the measurements arecompleted, press the ENTER key. Place the gauge on the dry barrel. If the gauge isnow displaying M1 0.00, it is waiting for the moisture equivalent of the dry barrel to bekeyed in. Key in this number and press the ENTER key. The gauge will display C1 0---and wait for the average count of the dry barrel to be keyed in. By pressing the STARTkey, the gauge will determine the average counts in about 4 minutes. When the gaugeis finished counting, press the ENTER key. The LCD will flash the word COMPUTE onthe display screen and then will show READY. Calibration is complete.

Correct operation can be verified by taking a measurement on one of the barrels. Lower the probe to the center of the barrel and press START. The displayed readingshould be within ±0.05 in/ft of the barrel's equivalent moisture content. If the test failsfor repeated measurements, repeat the standardization process and try the test again. The previously described tests for the S-503 should be used if the gauge still cannotmeasure the equivalent moisture content within ±0.05 in/ft.

As shown above, the barrels provide a quick means of verifying proper gaugeoperation. Simply measure the moisture content of one or both barrels before takingthe gauge into the field each day. All gauges should be more extensively checked outon the barrels to identify changes caused by electrical breakdown or drift at leastweekly. Standardization procedures should be followed any time drift is apparent.


29

NEUTRON PROBESTANDARD COUNT DETERMINATION

Probe No. H32074503

DATE: 6-10-85 OPERATOR: LM

Reading No. Count Rates

1. 29248 2. 29543 3. 29416 4. 29386 5. 29280 6. 29725 High 7. 29245 8. 29133 Low 9. 29603 High10. 2933011. 29100 Low12. 2939113. 2938214. 29648 High15. 2940116. 2942217. 2937018. 2941719. 29190 Low20. 29339

Total = 587629 ___ Average = 29381 oAvg = 171.4 ___ Average + oAvg = 29552 ___ {Acceptable Range Average - oAvg = 29210

STD DEV = 161.6 ___ Chi or RATIO = oAvg / STD DEV = 1.06 (Acceptable range = 0.75 - 1.25)

REMARKS: Probe is demonstrating good performance.

Figure 16Neutron Probe Standard Count Determination


30

Establishing Well-Watered Baseline

The well-watered baseline has been established for many common crops. Baseline coefficients for these crops have been shown previously in Table 2. Unfortunately, a desired crop may not be included in the table. In this event, a newbaseline must be developed.

The data needed to develop the new baseline for a crop must be collected in thefield. Infrared thermometer and Bendix psychrometer temperature measurementsshould be taken from as many recently irrigated fields as practical. Several readings should be made between 9 a.m. and 3 p.m. in each field to sample a range oftemperature and humidity conditions.

Analysis of the data requires computing the temperature depression (Tc-Ta) andthe vapor pressure deficit (VPD) for each set of measurements (see [B] and [C] in thehand calculation example to follow). New versions of the infrared thermometer displaythese measurements directly. A graph similar to Figure 4 is next prepared. Plot theVPD and (Tc-Ta) values for each set of measurements. The coefficients of the well-watered baseline are then determined using a standard linear regression process. Thecoefficients can now be used for making future CWSI computations.

Chapter 5 - Scheduling Irrigations

31

5 - SCHEDULING IRRIGATIONS

Starting Irrigation Service to a New Field

Once a field has been enrolled to receive irrigation scheduling services, severalpreliminary activities are required before active scheduling can begin. This discussionassumes that the necessary equipment and technicians are available to provide thescheduling service. Preliminary activities include selecting a site for the access tube,installing an access tube, and determining the "refill and full points."

Locating Access Tube Site

Selecting the proper site for tube installation requires analysis of several factorsincluding (1) accessibility to the tube, (2) method of irrigation, (3) soil type, and (4) cropstand and crop cover.

Accessibility. The tube should be located where it is readily accessiblefrom normally traveled roadways. If possible, tubes should be located away from areasthat may cause frequent hindrances to vehicle or foot travel. Tube accessibility willhave a bearing on the number of sites that can be read in a day by a technician.

Irrigation Method. With any type of flood irrigation system, the tube shouldbe located in the third quarter of the field below the head ditch. The first and secondquarters may be over irrigated and should be avoided. The fourth quarter of the field,furthest from the head ditch, may receive insufficient water or may have excess waterponded. Tube location is not critical with drip or sprinkler irrigation systems except thattubes should not be placed directly under a sprinkler head or adjacent to an emitter. Theoretically, all parts of the field receive the same amount of water from thesesystems. The extreme edges, high or low spots, or obvious dry spots in the field shouldbe avoided.

Soil Types. The access tube should be located in the area containing thepredominate or representative soil in the field to achieve most uniform results. Extremely sandy or clay soils should be avoided, if possible. Adjustments can be madein the refill point to accommodate these soil types if they represent significant portions ofthe field.

Crop Stand. The tubes should be located where crop stands are uniformand healthy. Stunted, bare, or weedy areas should be avoided. These areas do notrepresent normal consumptive use or soil conditions.


32

Installing Access Tubes

The installation of access tubes is a simple procedure, if the proper equipment isavailable and good work methods are employed. A 2-inch hole is bored several inchesdeeper than the length of the tube to be installed. The extra depth collects any soil thatmight slough off the sides of the hole as the tube is driven into the ground. A handauger is adequate but a power auger is preferred for boring the hole. Be careful toavoid over-sizing the hole diameter when using the power auger. There should be noair spaces around the tube. Loose soil deposited around the mouth of the hole shouldbe carefully cleaned away from the hole before inserting the tube.

The tube is inserted into the hole, sealed end first. It is pushed down by hand anddriven in flush with the ground surface using the tube driver. In some installations,tubes are not susceptible to equipment damage and do not need to be installed flushwith the ground. However, uniformly installing all tubes flush with the ground surfacewill insure that all measurements are taken at consistent depths. Any loose soil aroundthe top of the tube can be compacted. A brightly painted cap should be placed on thetube as soon as the installation is complete.

The tube location can be marked with a stake and flagging for easy location by thetechnician. In some situations the stake would disrupt cultural operations (like cuttingalfalfa). In this case, the stake should be placed at the edge of the field. It should bemarked with the number of paces between the stake and the tube.

Determining Refill Point

The refill point, or minimum allowable SMC at the time of irrigation, is establishedin the top foot of the soil profile using one or a combination of three criteria: (1) at whatdepletion should irrigation result in optimum yields; (2) at what depletion would the cropshow water stress; and (3) how dry would the farmer allow the soil to become beforeirrigating.

Using Optimum Moisture Content. Most crops can tolerate some stressbefore yields are affected. The moisture content at which irrigation should result inoptimum yield, can be identified by measuring the water content using the gauge andthe soil moisture tension using a tensiometer. Research has identified an optimummoisture tension for many crops. Irrigating before reaching the optimum tension canwaste water and retard plant growth. Delaying irrigations beyond the optimum tensionreduces crop yield. The refill point is the moisture content that occurs at the optimumsoil moisture tension. Unfortunately, the tensiometer has been unsatisfactory for large-scale irrigation scheduling activities. It has limited reliability and requires too muchlabor to keep the tensiometer operating properly. The accuracy of this method dependsupon the reliability of the tensiometers and how closely local conditions duplicateconditions where optimum tensions were determined.


33

Using Crop Water Stress Index (CWSI). The infrared thermometer isshowing promise in identifying the optimum moisture content. The CWSI, determinedwith the infrared thermometer, is compared to the SMC measured with the gauge. Therefill point is the moisture content that is measured when the optimum CWSI occurs. Aspreviously mentioned, the optimum CWSI for cotton and wheat are 0.45 and 0.3,respectively. Research is continuing to determine the optimum CWSI for other crops. This optimum value may vary depending upon the stage of growth. This is the mostaccurate method for determining the refill point.

The CWSI is computed using data collected with infrared thermometer andBendix psychrometer. The computations can be made using a computer or by hand. Newer versions of the infrared thermometer display the CWSI directly.

The computer program VEGY, developed by the Bureau of Reclamation,Yuma Area Office, can be used to make the computations. (Instructions for usingVEGY along with a program listing can be found in Appendix E.) Field readings fromthe Plant Foliage Temperature Data Sheet (see Figure 12) are entered into ProgramVEGY to compute the CWSI. Final output for two fields, S10 and 9, is shown inFigure 15. Note that field S10 is still well-watered with a CWSI of only 0.02. Field 9 isconsidered in a stress state with a CWSI of 0.45. Remember, CWSI ranges from 0.0 to1.0.

Hand calculating the CWSI is a rather lengthy procedure, where errors areeasily made. The field data used in the calculations are shown in Figure 18. Othervalues required in the computation are determined from Appendixes A and B. Theprocedure is illustrated in Figure 19 to show how the CWSI is derived.

Using Observation of Visible Stress. The soil moisture depletion at whichthe crop shows water stress can also be used to establish the refill point. The refill pointwould be the moisture content measured at the time stress is first noted. Salt or similarinfluences are accommodated by minor upward adjustments of the refill point until suchstress is not observable. Setting the refill point by this method is not as accurate aspreviously discussed methods. However, it will produce acceptable results that canimprove irrigation efficiency and crop yields.

Using Farmer's Judgement. Finally, the farmer's judgement andexperience can be used to set the refill point. The refill point would be the moisturecontent measured just before the beginning of a normal irrigation. This is usually theleast accurate method for determining refill points.

The refill points established using observed stress or the farmer's judgementare the easiest to obtain and often the most agreeable to the farmer. The othermethods can be used to refine these refill points. These refinements may have to bemade gradually over a period of several irrigations to be acceptable to the farmer.


34

CROP WATER STRESS INDEX COMPUTATIONS11/15/90Page 1

SAMPLE SAMPLE DATE TIME CROP FIELD 4/22/95 1410 WHEAT S10

DRY BULB WET BULB SAMPLE TEMPERATURES DATA TEMP TEMP (1) (2) (3) (4) (5) (6) (7) (8) WIND QUALITY 24.7 15.0 23.5 23.7 23.7 23.4 23.6 23.2 23.2 22.8 4 SE GOOD

SLOPE: -3.25

OFFSET: 3.38

TC-TA -1.31 C

VAPOR PRESSURE DEFICIT: 2.04 KPA

UPPER LIMIT: 5.61 C

CROP WATER STRESS INDEX: 0.22

RELATIVE HUMIDITY: 34.28%

- - - - - - - - - - SAMPLE SAMPLE DATE TIME CROP FIELD 4/22/95 1410 WHEAT 9

DRY BULB WET BULB SAMPLE TEMPERATURES DATA TEMP TEMP (1) (2) (3) (4) (5) (6) (7) (8) WIND QUALITY 27.7 14.2 28.9 29.0 28.4 26.4 27.5 27.5 27.2 27.3 10 N GOOD

SLOPE: -3.25

OFFSET: 3.38

TC-TA .07 C


UPPER LIMIT: 4.30 C



Figure 17Sample Printout from Program VEGY

Establishing Full Point

Both the refill and full points must be identified to establish the soil moistureholding capacity of any field. The full point, an approximation of field capacity, is theamount of moisture in the soil after initial drainage has removed the excess water. It isthe total of the moisture contents in each foot of soil profile. This measurement is taken1 or 2 days after the irrigation. The technician must be able to walk on the field withoutsinking into the soil or causing damage to the crop.


35

CROP WATER STRESS INDEX COMPUTATIONS11/15/90Page 1

SAMPLE SAMPLE DATE TIME CROP FIELD ------ ------ ---- ----- 7/25/95 1215 COTTON S10

DRY BULB WET BULB SAMPLE TEMPERATURES DATA TEMP TEMP (1) (2) (3) (4) (5) (6) (7) (8) WIND QUALITY -------- -------- ---- ---- ---- ---- ---- ---- ---- ---- ---- ------- 37.0 20.0 30.0 31.7 32.1 32.3 32.2 32.3 32.8 32.1 5 SSE GOOD

SLOPE: -2.24

OFFSET: 2.00

TC-TA -5.06 C


UPPER LIMIT: 3.09 C



Figure 18Data for CWSI Hand Calculation Example

Visiting Fields

Once access tube installation is complete and the refill point has been established, fieldirrigation scheduling can be started. Biweekly readings are taken at predetermineddepths. Cool-climate crops require less frequent readings. The readings, in inches ofmoisture, are plotted on a graph or entered into a computer. Usually, threemeasurements are taken in the first 3 feet of depth. Crops, such as fruit trees, thathave deeper penetrating roots will require additional readings at greater depths. Eachset of readings will give the current moisture content. Consecutive readings will give therate of water use by the crop.

Accurate moisture readings are essential to schedule irrigations precisely. Thetechnician must ensure that the equipment works properly, readings are taken correctly,and the site is protected. Before going to the field, the technician should verify theproper operation of the gauge. This is done by taking a measurement on one of thestandardization barrels. The reading should be within ±0.05 in/ft of the barrel's moisturecontent, if using the DR-503. The reading with an S-503 should be within plus or minusone standard deviation of the average count. (The average count was determinedduring standardization of the gauge).


36

Sample Date: 7-25-83 Crop: CottonField: 5 USBR Slope -1.70C = Centigrade USBR Intercept 1.90

(Tc-Ta) = -1.70 (VPD) + 1.92 (Equation of Well-Watered Baseline)

[B]. (Tc-Ta) = 31.94 C - 37.0 C db = -5.06 C (Actual Temperature Depression)

[A]. Upper Limit Value

Saturation Vapor Pressure of db Temp. (Appendix A) 47.067

Saturation Vapor Pressure of (db Temp. + 1.92) -52.161

Vapor Pressure Difference in MM Hq - 5.094

VPD in mm Hq = -5.094 x constant 1.3331 = VPD in mb - 6.791

VPD in mb = 6.791 ÷ constant 10 = VPD in Kpa - .679

(Tc - Ta) ul = -.679 x slope -1.70 + offset +1.92 + 3.07

[C]. Well-Watered Value

Saturation Vapor Pressure of db Temp. (Appendix A) 47.067

Relative Humidity in Field from Wet- and Dry-Bulb x .193

Existing Vapor Pressure in mm Hg 9.084- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Saturation Vapor Pressure of db Temp. 47.067

Existing Vapor Pressure in mm Hg - 9.084

Vapor Pressure Deficit in mm Hg 37.983- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Vapor Pressure Deficit in mm Hg 37.983

Constant x 1.3331

Vapor Pressure Deficit in mb 50.635

Vapor Pressure Deficit in mb ÷ 10 = Vapor Pressure Deficit in Kpa = 5.063

Vapor Pressure Deficit in Kpa = 5.063

(Tc-Ta)ww = 5.063 x (-1.70) + 1.92 - 6.687

CWSI = [B] - [C] = (-5.06) - (-6.687) = .167 or .17 (rounded) [A] - [C] ( 3.07) - (-6.687)

Note: If B is a larger number than C and they are both negative, the CWSI will be negative.

Figure 19Hand Calculating Crop Water Stress Index


37

Upon arriving at the field, the technician should exercise caution when approaching thesite, placing the gauge on the access tube, and taking readings. This is to insure thatthe crop growth around the tube is not trampled. Otherwise, the consumptive usemeasured at the site will not represent healthy crop stands in the remainder of the field. Protecting the crop is essential in maintaining good relations with the farmer.

Moisture readings are taken at about the 6-inch, 18-inch, and 30-inch depths. Thesereadings will be centered in the 1st-foot, 2nd-foot, and 3rd-foot zones. Fewer readingintervals may be required for shallow-rooted crops while deep-rooted crops may requiremore reading intervals. Readings are taken according to previously describedprocedures. The reading, read directly from the display or determined from aconversion table, should be written in the space provided and plotted immediately on afield graph. A sample field graph is shown in Figure 20. The reading can be plottedwhile the gauge is measuring the next depth so plotting does not require muchadditional time. (Note: Appendix D contains a blank field graph that can be duplicatedas needed for use in the field.)

Plotting readings as they are taken serves several purposes. The chance of anoccasional stray reading or error in interpretation can be quickly spotted and themeasurement retaken. If needed, the next irrigation can be immediately determined atthe site. Use a straight edge to project a line through the last two readings to the refillline. Read the date where the projected line and the refill line intersect. By noting thedate and the surrounding conditions, the technician may identify unusual conditions. Anything unusual should be brought to the farmer's attention. Several crops have beensaved by the alert observations of field technicians.

Before leaving the site, the technician should insure that the probe has been retractedand securely locked in place in the gauge case. The cap should also be securelyreplaced on the tube. Otherwise, irrigation water could fill the tube and damage theprobe the next time a reading is taken.

Field technicians have noted that readings taken at the access tube site may, in somecases, not always represent conditions found throughout the majority of the field. Themost frequently occurs when the field is not uniformly irrigated. As a result, some partsof the field may be under irrigated while other parts are over irrigated. When thetechnician suspects that this may be the case, a hand soil probe should be used tosample several locations in the field and use the "feel method" to determine andcompare moisture contents. When this condition is noted, the farmer should beadvised. This effort may help save a portion of the crop and offers an opportunity toconsult with the farmer on ways to improve the efficiency of the irrigation program.

After measuring all the sites on the assigned route, the technician should submit thedata for computer preparation of schedules, if a computer is being used. Otherwise, thetechnician should transfer projected dates and amounts to a summary report sheet thatcan be given to the farmer. If printed irrigation schedules are used, the technicianshould compare projected dates shown on the printout with the graphs in the field book. Any corrections should be entered into the computer. A new schedule should be


38

Figu

re 2

0S

ampl

e Fi

eld

Gra

ph


39

printed so the printed dates and amounts agree with the field graphs. A simplesummary form that can be given to the farmers is shown in Figure 21. A blank form is inAppendix D. A computer-generated irrigation schedule is shown in Figure 22.

Contacting Farmers

Several methods are available to get the completed report or schedule to the farmer. The report or schedule can be sent by mail, delivered to the secretary or a familymember, put in farmer's truck, etc. However, the most effective method is by directcontact. Experience has repeatedly shown in the LC Region that the farmers who mostclosely follow the recommendations have received the most frequent personal contactby the field technicians. Personal contacts can include a walk through the field with thefarmer, a roadside discussion, a meeting at the local coffee shop, or a visit to thefarmer's home or office. Any other means where the technician and farmer can discussthe farmer's irrigation activities, field and crop conditions, and any other informationabout the farmer's overall operation are also appropriate. Regular meeting schedulesare often impossible to establish with farmers. Other means to get scheduling reports tothe farmer in a timely manner will beneficially supplement personal contacts.

Remember, good personal contacts are essential to effective irrigation scheduling.


40

DATE_________________________ DATE________________________

WATER USER __________________ WATER USER _________________

CONTRACT NO. ________________ CONTRACT NO. _______________

FIELDNO.

PROJECTEDIRRIG. DATE

REFILLAMOUNT

FIELDNO.

PROJECTEDIRRIG. DATE

REFILLAMOUNT

303-41 (Rev. 5-92) 303-41 (Rev. 5-92)(File Copy) (Farmer's Copy)

Figure 21Sample Farmer Report Form


41

BUREAU OF INDIAN AFFAIRS Route 1 Box 9c Parker, AZ 85344 662-4358

DATE: APR 26 CRIT FARMS P O BOX 1028 PARKER AZ 85344 ------------IRRIGATIONS------------ FIELD, CROP ------NEXT------ ------LAST------ AND ACRES ----AMT--- ----AMT--- ------------ DATE IN. AC-FT DATE IN. AC-FT 12 ALF 38 5/ 3 5.7 18.0 4/19 4.2 13.3 16 ALF 37 5/ 3 5.7 17.6 4/19 5.4 16.7 17 ALF 37 5/ 9 5.7 17.6 4/21 3.0 9.3 21 ALF 36 4/29 4.0 12.0 4/16 .0 .0 22 ALF 37 5/ 9 5.6 15.4 4/21 6.8 21.0 26 ALF 36 5/ 7 5.6 16.8 4/16 11.9 35.7 27 ALF 36 5/ 7 4.2 12.6 4/18 10.8 32.4 30 ALF 35 5/ 7 4.0 11.9 4/18 8.7 25.4 31 ALF 35 5/ 7 5.3 15.5 4/18 11.1 32.4 41 ALF 38 4/30 4.2 13.2 4/18 6.3 20.0 45 ALF 37 ***** 4/20 .0 .0 46 ALF 35 5/ 3 4.0 12.0 4/18 .0 .0 48 ALF 35 4/29 4.6 13.8 4/18 .0 .0 49 ALF 38 4/29 3.5 10.9 4/18 .0 .0 56 ALF 35 4/23* 3.5 10.5 4/14 7.4 21.6 2- 2 ALF 32 4/27 3.4 9.1 4/14 17.3 46.1 2- 3 ALF 25 4/26 5.0 10.4 4/13 3.2 6.7 2- 8 ALF 16 4/26 3.4 4.2 4/14 5.0 6.7 2-11 ALF 21 4/25* 5.1 8.9 4/13 4.5 7.9 2-13 ALF 52 4/28 4.2 16.2 4/12 4.2 18.2 2-16 ALF 29 4/27 4.5 10.9 4/10 8.1 19.6 2-17 ALF 30 4/27 4.6 11.5 4/10 3.9 9.8

* - FIELD OVERDUE FOR IRRIGATION ***** - IRRIGATION NOT REQUIRED BEFORE MAY 10

Figure 22Sample Computer Generated Farm Irrigation Schedule

Appendix A

APPENDIX A

Relative Humidity, Percent – Centigrade Temperatures

Appendix A

A-1

Appendix ARelative Humidity, Percent - Centigrade Temperatures

[Pressure=29.24 in.]

Airtemperature(t)

Depression of wet-bulb thermometer(t-t')

7.6 7.7 7.8 7.9 8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9 9.0

8.................. 12 11 10 9 8 7 6 5

9.................. 16 15 14 13 12 11 10 9 8 7 6 5

10................. 19 18 17 16 15 14 13 12 11 10 9 8 7 7 6

11................. 22 21 20 19 18 17 16 15 14 13 13 12 11 10 9

12................. 24 23 22 22 21 20 19 18 17 16 16 15 14 13 13

13................. 27 26 25 24 23 22 22 21 20 19 18 17 17 16 15

14................. 29 28 27 27 26 25 24 23 22 22 21 20 19 18 18

15................. 31 30 29 28 27 27 26 25 24 24 23 22 22 21 20

16................. 33 32 32 31 30 29 29 28 27 26 26 25 24 23 23

17................. 35 34 34 33 32 31 31 30 29 28 28 27 26 26 25

18................. 37 36 35 35 34 33 33 32 31 30 30 29 28 28 27

19................ 39 38 37 36 36 35 34 34 33 32 32 31 30 30 29

20................. 40 39 39 38 37 37 36 35 35 34 33 33 32 31 31

21................. 42 41 40 40 39 38 38 37 36 36 35 34 34 33 32

22................. 43 42 42 41 40 40 39 39 38 37 37 36 35 35 34

23................. 44 44 43 42 42 41 41 40 39 39 38 38 37 36 36

24................. 46 45 44 44 43 43 42 41 41 40 40 39 38 38 37

25................. 47 46 46 45 44 44 43 43 42 41 41 40 40 39 39

26................. 48 47 47 46 46 45 44 44 43 43 42 42 41 40 40

27................. 49 48 48 47 47 46 46 45 44 44 43 43 42 42 41

28................. 50 49 49 48 48 47 47 46 46 45 44 44 43 43 42

29................ 51 50 50 49 49 48 48 47 47 46 46 45 44 44 43

30................. 52 51 51 50 50 49 49 48 48 47 47 46 45 45 44

31................. 53 52 52 51 51 50 50 49 49 48 48 47 47 46 45

32................. 54 53 52 52 51 51 50 50 49 49 48 48 47 47 46

33................. 54 54 53 53 52 52 51 51 50 50 49 49 48 48 47

34................. 55 55 54 54 53 53 52 52 51 51 50 50 49 49 48

35................. 56 55 54 54 54 53 53 52 52 51 51 50 50 49 49

36................. 56 56 55 55 54 54 53 53 53 52 52 51 51 50 50

37................. 57 57 56 56 55 55 54 54 53 53 52 52 51 51 51

38................. 58 57 57 56 56 55 55 55 54 54 53 53 52 52 51

39................. 58 58 57 57 57 56 56 55 55 54 54 53 53 52 52

40................. 59 59 58 58 57 57 56 56 55 54 54 54 54 53 53

41................. 60 59 59 58 58 57 57 56 56 56 55 55 54 54 53

42................. 60 60 59 59 58 58 57 57 57 56 56 55 54 54 54

43................. 61 60 60 59 59 58 58 58 57 57 56 56 55 55 55

44................. 61 61 60 60 59 59 58 58 58 57 57 56 56 56 55

Appendix A

A-2

Appendix A

Relative humidity, percent-centigrade temperatures-Continued[Pressure=29.24 in.]

Air tempreature(t) Depression of wet-bulb thermometer(t-t')

9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 9.9 10.0 10.1 10.2 10.3 10.4 10.5

10.................... 5

11.................... 8 7 6 6 5

12.................... 11 10 10 9 8 7 6 5 5

13................... 14 13 13 12 11 10 9 9 8 7 6 6 5

14................... 17 16 15 15 14 13 12 11 11 10 9 8 8 7 6

15................... 20 19 18 17 16 16 15 14 13 13 12 11 11 10 9

16................... 22 21 20 20 19 18 17 17 16 15 15 14 13 13 12

17................... 24 23 23 22 21 21 20 19 18 18 17 16 16 15 14

18................... 26 26 25 24 23 23 22 21 21 20 19 19 18 17 17

19................... 28 28 27 26 26 25 24 24 23 22 22 21 20 20 19

20................... 30 29 29 28 28 27 26 26 25 24 24 23 22 22 21

21................... 32 31 31 30 29 29 28 28 27 26 26 25 24 24 23

22................... 34 33 32 32 31 30 30 29 29 28 28 27 26 26 25

23................... 35 34 34 33 33 32 32 31 30 30 29 29 28 27 27

24................... 37 36 35 35 34 34 33 33 32 31 31 30 30 29 29

25................... 38 37 37 36 36 35 35 34 33 33 32 32 31 31 30

26................... 39 39 38 38 37 37 36 35 35 34 34 33 33 32 32

27................... 41 40 39 39 38 38 37 37 36 36 35 35 34 34 33

28................... 42 41 41 40 40 39 39 38 38 37 36 36 35 35 34

29................... 43 42 42 41 41 40 40 39 39 38 38 37 37 36 36

30................... 44 43 43 42 42 41 41 40 40 39 39 38 38 37 37

31................... 45 44 44 43 43 42 42 41 41 40 40 40 39 39 38

32................... 46 45 45 44 44 43 43 42 42 41 41 41 40 40 39

33................... 47 46 46 45 45 44 44 43 43 42 42 42 41 41 40

34................... 48 47 47 46 46 45 45 44 44 43 43 43 42 42 41

35................... 49 48 48 47 47 46 46 45 45 44 44 44 43 43 42

36................... 49 49 48 48 48 47 47 46 46 45 45 44 44 44 43

37................... 50 50 49 49 48 48 47 47 47 46 46 45 45 44 44

38................... 51 50 50 50 49 49 48 48 47 47 46 46 46 45 45

39................... 52 51 51 50 50 49 49 48 48 48 47 47 46 46 46

40................... 52 52 51 51 51 50 50 49 49 48 48 48 47 47 46

41................... 53 52 52 52 51 51 50 50 50 49 49 48 48 47 47

42................... 53 53 53 52 52 51 51 51 50 50 49 49 48 48 48

43................... 54 54 53 53 52 52 52 51 51 50 50 50 49 49 48

44................... 55 54 54 53 53 53 52 52 51 51 51 50 50 49 49

Appendix A

A-3

Appendix A


Air tempreature(t) Depression of wet-bulb thermometer(t-t')

10.6 10.7 10.8 10.9 11.0 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 11.9 12.0

14........................ 6 5

15........................ 8 8 7 6 6 5

16........................ 11 10 10 9 8 8 7 6 6 5

17...................... 14 13 12 12 11 10 10 9 8 8 7 6 6 5

18...................... 16 15 15 14 14 13 12 12 11 10 10 9 8 8 7

19...................... 18 18 17 17 16 15 15 14 13 13 12 12 11 10 10

20...................... 21 20 19 19 18 18 17 16 16 15 15 14 13 13 12

21...................... 23 22 22 21 20 20 19 19 18 17 17 16 16 15 14

22...................... 25 24 23 23 22 22 21 20 20 19 19 18 18 17 17

23...................... 26 26 25 25 24 24 23 22 22 21 21 20 20 19 19

24...................... 28 27 27 26 26 25 25 24 24 23 23 22 21 21 20

25...................... 30 29 29 28 28 27 26 26 25 25 24 24 23 23 22

26...................... 31 31 30 30 29 28 28 27 27 26 26 25 25 24 24

27...................... 33 32 32 31 31 30 30 29 29 28 28 27 27 26 26

28...................... 34 33 33 32 32 31 31 30 30 29 29 28 28 27 27

29...................... 35 35 34 34 33 33 32 32 31 31 30 30 29 29 28

30...................... 36 36 35 35 35 34 34 33 33 32 32 31 31 30 30

31...................... 38 37 37 36 36 35 35 34 34 33 33 32 32 32 31

32...................... 39 38 38 37 37 36 36 36 35 35 34 34 33 33 32

33...................... 40 39 39 38 38 37 37 36 36 36 35 35 34 34 33

34...................... 41 40 40 39 39 39 38 38 37 37 36 36 35 35 35

35...................... 42 41 41 40 40 40 39 39 38 38 37 37 37 36 36

36...................... 43 42 42 41 41 40 40 40 39 39 38 38 38 37 37

37...................... 44 43 43 42 42 41 41 41 40 40 39 39 38 38 38

38...................... 44 44 44 43 43 42 42 41 41 41 40 40 39 39 39

39...................... 45 45 44 44 43 43 43 42 42 42 41 41 40 40 39

40...................... 46 46 45 45 44 44 44 43 43 42 42 42 41 40 40

41...................... 47 46 46 45 45 45 44 44 43 43 43 42 42 41 41

42...................... 47 47 46 46 46 45 45 45 44 44 43 43 43 42 42

43...................... 48 48 47 47 46 46 46 45 45 44 44 44 43 43 43

44...................... 49 48 48 47 47 47 46 46 46 45 45 44 44 44 43

Appendix A

A-4

Appendix A


AirTemperature

(t)

Depression of wet-bulb thermometer(t-t')

12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8 12.9 13.0 13.1 13.2 13.3 13.4 13.5

18................ 7 6 5 5

19................ 9 9 8 7 7 6 6 5

20................ 12 11 10 10 9 9 8 7 7 6 6 5 5

21................ 14 13 13 12 12 11 10 10 9 9 8 8 7 7 6

22................ 16 15 15 14 14 13 13 12 12 11 10 10 9 9 8

23................ 18 17 17 16 16 15 15 14 14 13 13 12 12 11 11

24................ 20 19 19 18 18 17 17 16 16 15 15 14 14 13 13

25................ 22 21 21 20 20 19 19 18 18 17 17 16 16 15 15

26................ 23 23 22 22 21 21 20 20 19 19 19 18 18 17 17

27................ 25 25 24 24 23 23 22 22 21 21 20 20 19 19 18

28................ 27 26 26 25 25 24 24 23 23 22 22 21 21 20 20

29................ 28 28 27 27 26 26 25 25 24 24 23 23 22 22 22

30................ 29 29 28 28 28 27 27 26 26 25 25 24 24 24 23

31................ 31 30 30 29 29 28 28 28 27 27 26 26 25 25 25

32................ 32 31 31 31 30 30 29 29 28 28 28 27 27 26 26

33................ 33 32 32 32 31 31 30 30 30 29 29 28 28 28 27

34................ 34 34 33 33 32 32 32 31 31 30 30 30 29 29 28

35................ 35 35 34 34 34 33 33 32 32 32 31 31 30 30 30

36................ 36 36 35 35 35 34 34 33 33 33 32 32 31 31 31

37................ 37 37 36 36 36 35 35 34 34 34 33 33 33 32 32

38................ 38 38 37 37 37 36 36 35 35 35 34 34 33 33 33

39................ 39 39 38 38 38 37 37 36 36 36 35 35 34 34 34

40................ 40 40 39 39 38 38 38 37 37 36 36 36 35 35 35

41................ 41 40 40 40 39 39 39 38 38 37 37 37 36 36 36

42................ 42 41 41 40 40 40 39 39 39 38 37 37 37 37 36

43................ 42 42 42 41 41 40 40 40 39 39 39 38 38 38 37

44................ 43 43 42 42 42 41 41 40 40 40 39 39 39 38 38

Appendix B

APPENDIX B

Vapor Pressure of Water Below 100 oC

Appendix B

B-1

VAPOR PRESSURE OF WATER BELOW 100°Pressure of aqueous vapor over water in mm of Hg for temperatures from -15.8 to 100° C

Values for fractional degrees between 50 and 89 were obtained by interpolation.

Temp°C

0.0 0.2 0.4 0.6 0.8 Temp°C

0.0 0.2 0.4 0.6 0.8

-15 1.436 1.414 1.390 1.368 1.345 12 10.518 10.658 10.799 10.941 11.085

-14 1.500 1.534 1.511 1.483 1.460 13 11.231 11.379 11.528 11.680 11.833

-13 1.691 1.685 1.637 1.611 1.585 14 11.987 12.444 12.302 12.462 12.624

-12 1.834 1.804 1.776 1.748 1.720 15 12.788 12.953 13.121 13.290 13.461

-11 1.987 1.955 1.924 1.893 1.863 16 13.643 13.809 13.897 14.166 14.347

-10 2.149 2.116 2.084 2.050 2.018 17 14.530 14.715 14.903 15.092 15.284

- 9 2.326 2.289 2.254 2.219 2.184 18 15.477 15.673 15.871 16.071 16.272

- 8 2.514 2.475 2.437 2.399 2.362 19 16.477 16.685 16.894 17.105 17.319

- 7 2.715 2.674 2.633 2.593 2.553 20 17.535 17.753 17.974 18.197 18.422

- 6 2.931 2.887 2.843 2.800 2.757 21 18.650 18.880 19.113 19.349 19.587

- 5 3.163 3.115 3.069 3.022 2.976 22 19.827 20.070 20.316 20.565 20.815

- 4 3.410 3.359 3.309 3.259 3.211 23 21.068 21.234 21.583 21.845 22.110

- 3 3.673 3.620 3.567 3.514 3.461 24 22.377 22.648 22.922 23.198 23.476

- 2 3.956 3.808 3.841 3.785 3.730 25 23.756 24.039 24.326 24.617 24.912

- 1 4.258 4.196 4.135 4.075 4.016 26 25.209 25.509 25.812 26.117 26.426

- 0 4.579 4.513 4.448 4.385 4.320 27 26.739 27.055 27.374 37.696 28.021

0 4.579 4.647 4.715 4.785 4.855 28 28.349 28.680 29.015 29.354 29.697

1 4.296 4.998 5.070 5.144 5.219 29 30.043 30.392 30.745 31.102 31.461

2 5.294 5.370 5.447 5.525 5.605 30 31.824 32.191 32.561 32.934 33.312

3 5.685 5.766 5.848 5.931 6.015 31 33.695 34.082 34.471 34.864 35.261

4 6.101 6.187 6.274 6.363 6.453 32 35.663 36.068 36.477 36.891 37.308

5 6.543 6.635 6.728 6.822 6.917 33 37.729 38.155 38.584 39.018 39.457

6 7.013 7.111 7.209 7.309 7.411 34 39.898 40.344 40.796 41.251 41.710

7 7.513 7.617 7.722 7.828 7.936 35 42.175 42.644 43.117 43.595 44.078

8 8.045 8.155 8.267 8.380 8.494 36 44.563 45.054 45.549 46.050 46.556

9 8.609 8.727 8.845 8.965 9.086 37 47.067 47.582 48.102 48.627 49.157

10 9.209 9.333 9.458 9.585 9.714 38 49.692 50.231 50.774 51.323 51.879

11 9.844 9.976 10.109 10.244 10.380 39 52.442 53.009 53.580 54.156 54.737

Appendix B

B-2

VAPOR PRESSURE OF WATER BELOW 100°-ContinuedPressure of aqueous vapor over water in mm of Hg for temperatures from -15.8 to 100° C

Values for fractional degrees between 50 and 89 were obtained by interpolation.

Temp°C

0.0 0.2 0.4 0.6 0.8 Temp°C

0.0 0.2 0.4 0.6 0.8

40 55.324 55.91 56.51 57.11 57.72 71 243.9 246.0 248.2 250.3 252.4

41 58.34 58.96 59.58 60.22 60.86 72 254.6 256.8 259.0 261.2 263.4

42 61.50 62.14 62.80 63.46 64.12 73 265.7 268.0 270.2 272.6 274.8

43 64.80 65.48 66.16 66.86 67.56 74 277.2 279.4 281.8 284.2 286.6

44 68.26 68.97 69.69 70.41 71.14 75 289.1 291.5 294.0 296.4 298.8

45 71.88 72.62 73.36 74.12 74.88 76 301.4 303.8 306.4 308.9 311.4

46 75.65 76.43 77.21 78.00 78.80 77 314.1 316.6 319.2 322.0 324.6

47 79.60 80.41 81.23 82.05 82.87 78 327.3 330.0 332.8 335.8 338.2

48 83.71 84.56 85.42 80.28 87.14 79 341.0 343.8 346.6 349.4 352.2

49 88.02 38.90 39.90 90.69 91.59 80 355.1 358.0 361.0 363.8 366.8

50 92.51 93.5 94.4 95.3 96.3 81 369.7 372.6 375.6 378.8 381.8

51 97.20 98.2 99.1 100.1 101.1 82 384.9 388.0 391.2 394.4 397.4

52 102.09 103.1 104.1 105.1 106.2 83 400.6 403.8 407.0 410.2 413.6

53 107.20 108.2 109.3 110.4 111.4 84 416.8 420.2 423.6 426.8 430.2

54 112.51 113.6 114.7 115.8 116.9 85 433.6 437.0 440.4 444.0 447.5

55 118.04 119.1 120.3 121.5 122.6 86 450.9 454.4 458.0 461.6 465.2

56 123.80 125.0 126.2 127.4 128.6 87 468.7 472.4 476.0 479.8 483.4

57 129.82 131.0 132.3 133.5 134.7 88 487.1 491.0 494.7 498.5 502.2

58 136.08 137.3 138.5 139.9 141.2 89 506.1 510.0 513.9 517.8 521.8

59 142.60 143.9 145.2 146.6 148.0 90 525.76 529.77 533.80 537.86 541.95

60 149.38 150.7 152.1 153.5 155.0 91 546.05 550.18 554.35 558.53 562.75

61 156.43 157.8 159.3 160.8 162.3 92 566.99 571.26 575.55 579.87 584.22

62 163.77 165.2 166.8 168.3 169.8 93 538.60 593.00 597.43 601.89 600.38

63 171.38 172.9 174.5 176.1 177.7 94 610.90 615.44 620.01 624.61 629.24

64 179.31 180.9 182.5 184.2 185.8 95 633.90 638.58 643.30 648.05 652.82

65 187.54 189.2 190.9 192.6 194.3 96 657.62 662.45 667.31 672.20 677.12

66 196.09 197.8 199.5 201.3 203.1 97 682.07 687.04 692.05 697.10 702.17

67 204.96 206.8 208.6 210.5 212.3 98 707.27 712.40 717.56 722.75 727.98

68 214.17 216.0 218.0 219.9 221.8 99 733.24 738.24 743.85 749.20 754.58

69 223.73 225.7 227.7 229.7 231.7 100 760.00 765.45 770.93 776.44 782.00

70 233.7 235.7 237.7 239.7 241.8 101 787.57 793.18 798.82 804.50 810.21

Appendix C

APPENDIX C

Equipment Drawings and Specifications

Appendix C

C-1

Figu

re C

-1.

Neu

tron

Moi

stur

e G

auge

Acc

ess

Tube

Ada

pter

Appendix D

D-1

APPENDIX D

Blank Field Data Sheets

Appendix E - Using Program VEGY

APPENDIX E

Using Program VEGY


E-1

USING PROGRAM VEGY

Program VEGY is intended to assist in the computation of the Crop Water Stress Index(CWSI). VEGY was originally written in FORTRAN by the Yuma Area Office in about1985 for use on the VAX computer. The version discussed here has been converted toBASIC for use on IBM-compatible, personal computers. It can be run with GWBASIC orQBASIC on MS-DOS computers. The program listing is also included for thoseventuresome individuals who wish to enter the program by hand or convert it to VisualBasic so that it can be run on MS-Windows computers.

Program VEGY is a menu-driven program that presents the user with fill-in-the-blanksscreen images for data entry. From the main menu, the user can do the following:

1. Create a new data file,2. Add data to an existing data file,3. Correct data in an existing data file,4. Compute the CWSI,5. Compute the slope and offset for a crop, and6. Exit the program.

Program VEGY and its accompanying crop name file, CROPS.DAT, can be located inany convenient subdirectory on the hard drive. It can also be run from a floppy disk ifdesired. If other Reclamation WMC software programs are in use, VEGY should belocated in the same subdirectory.

To start Program VEGY, use the appropriate commands under the followingcircumstances:

GWBASIC (early versions of MS-DOS) - Type: GWBASIC VEGYQBASIC (MS-DOS ver. 5.0 & later) - Type: QBASIC /R VEGYCompiled Program - Type: VEGY

VEGY will display a main menu showing the options listed above. After selecting anoption, VEGY will ask for the name of the data file containing existing data or the nameof a new file being created. Use an easily understood and remembered name likeVEGYDATA.DAT. You may want to use separate files for each batch of data beingprocessed, separate files for different crops, etc. A word of caution here. Data fromvarious crops can be mixed when computing the CWSI but should not be mixed whencomputing new a slope and offset for a crop. Use a separate file for each crop.


E-2

Program Listing - VEGY.BAS

10 ' - PROGRAM VEGY.BAS20 ' DATA ENTRY PROGRAM CREATED BY DATASYS30 ' AUTHOR: Michael Stuver40 ' DATE: October 24, 199550 DIM SL$(30),DL$(50),CROP$(100),VALID$(16),SKEY$(50),RPOINTER(50)60 FF$=CHR$(12)70 NP=180 SCREEN 090 COLOR 15,1100 FOR I=1 TO 20 110 READ SL$(I)120 NEXT I130 FOR I=1 TO 16140 READ VALID$(I)150 NEXT I160 DATA " Program VEGY Data Entry Form"170 DATA ""180 DATA ""190 DATA "Sampling Date (7/21/95 = 072195): ....... "200 DATA ""210 DATA "Sampling Time (8:15am = 0815 & 2:15pm = 1415): ...."220 DATA ""230 DATA "Crop Code: .. Field designation: .........."240 DATA ""250 DATA "Dry-Bulb Temperature (Deg C): ..... Wet-Bulb Temperature (Deg C): ....."260 DATA ""270 DATA " Temperatures (Deg C)"280 DATA " (1): ..... (2): ..... (3): ..... (4): ..... "290 DATA " (5): ..... (6): ..... (7): ..... (8): ....."300 DATA ""310 DATA "Wind Speed: .. Wind Direction: ..."320 DATA ""330 DATA "Slope: ..... Offset: ....."340 DATA ""350 DATA "Data Quality Code (1=good, 2=fair, 3=poor): .."360 DATA "N ","NNE","NE ","ENE","E ","ESE","SE ","SSE"370 DATA "S ","SSW","SW ","WSW","W ","WNW","NW ","NNW"380 RESTORE390 OPEN "I",1,"CROPS.DAT"400 IF EOF(1) THEN 430410 INPUT#1,I,CROP$(I),Z$420 GOTO 400430 CLOSE(1)440 CLS450 PRINT "PROGRAM VEGY PC Ver. 1.0 25 October 1995"460 PRINT470 PRINT " MAIN MENU"480 PRINT490 PRINT " 1 - Start new data file"500 PRINT " 2 - Add data to existing file"510 PRINT " 3 - Correct data in existing file"520 PRINT " 4 - Compute and print CWSI reports"530 PRINT " 5 - Compute new Slope and Offset"540 PRINT " (Do not mix data for several crops in"550 PRINT " the same data file. Use separate Files.)"560 PRINT " 6 - Exit"570 PRINT580 PRINT " Please Enter your choice: ";590 COLOR 14,1600 LINE INPUT A$610 COLOR 15,1620 SEL=VAL(A$)


E-3

630 IF SEL>0 AND SEL<=9 THEN 660640 PRINT CHR$(7):GOSUB 10120650 GOTO 580660 ON SEL GOTO 680,870,1120,1490,1650,1780670 '680 ' CHOICE 1 - START NEW DATA FILE690 '700 K=1710 PRINT720 PRINT "Enter name of data file: ";730 COLOR 14,1740 LINE INPUT D$750 COLOR 15,1760 CLS770 FOR I=1 TO 20 780 PRINT SL$(I)790 NEXT I800 'OPEN "O",3,D$810 GOSUB 1830 ' CALL DATA ENTRY SUBROUTINE820 IF QUIT=1 THEN 830 ELSE 810830 NR=K-1840 'GOSUB 10030 ' PRINT UPDATED DATA FILE845 GOSUB 10200 ' SORT AND PRINT UPDATED DATA FILE850 GOTO 440860 '870 ' CHOICE 2 - ADD DATA TO EXISTING FILE880 '890 PRINT900 PRINT "Enter name of data file: ";910 COLOR 14,1920 LINE INPUT D$930 COLOR 15,1940 OPEN "I",#1,D$950 K=0960 IF EOF(1) THEN 1000970 K=K+1980 LINE INPUT#1,DL$(K)990 GOTO 9601000 CLS1010 K=K+11020 FOR I=1 TO 20 1030 PRINT SL$(I)1040 NEXT I1050 QUIT =0 1060 GOSUB 1830 ' CALL DATA ENTRY SUBROUTINE1070 IF QUIT=1 THEN 1080 ELSE 10601080 CLOSE1081 NR=K-11082 'LPRINT NR1090 'GOSUB 10030 ' PRINT UPDATED DATA FILE1091 GOSUB 10200 ' SORT AND PRINT UPDATED DATA FILE1100 GOTO 4401110 '1120 ' CHOICE 3 - SUBROUTINE TO CORRECT EXISTING DATA1130 '1140 IF D$>"" THEN 12001150 PRINT1160 PRINT "Enter name of data file: ";1170 COLOR 14,11180 LINE INPUT D$1190 COLOR 15,11200 OPEN "I",1,D$1210 K=01220 IF EOF(1) THEN 12601230 K=K+1


E-4

1240 LINE INPUT#1,DL$(K)1250 GOTO 12201260 CLOSE1270 NR=K1280 CLS1290 FOR I=1 TO 20 1300 PRINT SL$(I)1310 NEXT I1320 FOR K=1 TO NR1330 GOSUB 67901340 LOCATE 23,1:PRINT "Is this record correct (Y/N)? Y ";1350 LOCATE 23,311360 COLOR 14,11370 LINE INPUT B$1380 COLOR 15,11390 LOCATE 23,1:PRINT " "1400 IF B$="y" OR B$="Y" THEN 14501410 IF B$="" THEN 14501420 QUIT=01430 GOSUB 18301440 IF QUIT=1 THEN 14601450 NEXT K1460 'GOSUB 10030 ' PRINT UPDATED DATA FILE1461 GOSUB 10200 ' SORT AND PRINT UPDATED DATA FILE1470 GOTO 4401480 '1490 ' CHOICE 4 - COMPUTE AND PRINT CWSI1500 '1510 IF D$<="" THEN 1520 PRINT1530 PRINT "Enter name of data file: ";1540 COLOR 14,11550 LINE INPUT D$1560 COLOR 15,11570 END IF1580 GOSUB 72301590 LPRINT FF$1600 LOCATE 23,1,11610 PRINT " "1620 CLOSE1630 GOTO 4401640 '1650 ' CHOICE 5 - COMPUTE NEW SLOPE AND OFFSET1660 '1670 IF D$>"" THEN 17301680 PRINT1690 PRINT "Enter name of data file: ";1700 COLOR 14,11710 LINE INPUT D$1720 COLOR 15,11730 OPEN "I",2,D$1740 GOSUB 87601750 CLOSE1760 GOTO 4401770 '1780 ' CHOICE 6 - EXIT PROGRAM1790 '1800 LOCATE 23,1,11810 PRINT " "1820 SYSTEM1830 '1840 ' --- SUBROUTINE TO ENTER OR CORRECT ONE LINE OF DATA1850 '1860 ' - Sampling Date1870 ' - FIELD 1 INTEGER, SIZE I 7 REPEATED WITH 'ENTER'


E-5

1880 '1890 LOCATE 23,1:PRINT "ENTER '\' TO END DATA ENTRY ";1900 LOCATE 4,1:PRINT MID$(SL$(4),1,42);1910 LOCATE 4, 36,11920 COLOR 14,11930 LINE INPUT I$1940 COLOR 15,11950 IF LEFT$(I$,1)="\" THEN 1960 ELSE 19801960 QUIT=11970 RETURN 1980 Z=LEN(I$):IF Z=0 THEN 21401990 Z=LEN(I$)2000 FOR J=1 TO Z2010 IF MID$(I$,J,1)= CHR$(45) THEN 2040 2020 IF MID$(I$,J,1)>CHR$(47) AND MID$(I$,J,1)<CHR$(58) THEN 2040 2030 PRINT CHR$(7):GOSUB 10120:GOTO 1830 2040 NEXT J2050 IF Z=5 THEN 2060 F1$=" 0"+I$2070 GOTO 21402080 END IF2090 IF Z=6 THEN2100 F1$=" "+I$2110 GOTO 21402120 END IF2130 GOTO 20302140 IF MID$(F1$,2,2)<"01" OR MID$(F1$,2,2)>"12" THEN 20302150 IF MID$(F1$,4,2)<"01" OR MID$(F1$,4,2)>"31" THEN 20302160 COLOR 14,12170 LOCATE 4,36,1:PRINT USING"\ \";F1$2180 COLOR 15,12190 LOCATE 22,1:PRINT " "2200 '2210 ' - Sampling Time2220 ' - FIELD 2 INTEGER, SIZE I 4 REPEATED WITH 'ENTER'2230 '2240 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";2250 LOCATE 6,1:PRINT MID$(SL$(6),1,52);2260 LOCATE 6, 49,12270 COLOR 14,12280 LINE INPUT I$2290 COLOR 15,12300 IF LEFT$(I$,1)="\" THEN 1830 2310 Z=LEN(I$):IF Z=0 THEN 2390 2320 Z=LEN(I$)2330 FOR J=1 TO Z2340 IF MID$(I$,J,1)= CHR$(45) THEN 2370 2350 IF MID$(I$,J,1)>CHR$(47) AND MID$(I$,J,1)<CHR$(58) THEN 2370 2360 PRINT CHR$(7):GOSUB 10120:GOTO 2200 2370 NEXT J2380 F2=VAL(I$)2390 IF F2<500 OR F2>2000 THEN 23602400 COLOR 14,12410 LOCATE 6,49,1:PRINT USING"####";F22420 COLOR 15,12430 LOCATE 22,1:PRINT " "2440 F2$=" "2450 RSET F2$=STR$(F2)2460 '2470 ' - Crop Code2480 ' - FIELD 3 INTEGER, SIZE I 2 REPEATED WITH 'ENTER'2490 '2500 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";2510 LOCATE 8,1:PRINT MID$(SL$(8),1,36);2520 LOCATE 8, 13,1


E-6

2530 COLOR 14,12540 LINE INPUT I$2550 COLOR 15,12560 IF LEFT$(I$,1)="\" THEN 2200 2570 Z=LEN(I$):IF Z=0 THEN 2650 2580 Z=LEN(I$)2590 FOR J=1 TO Z2600 IF MID$(I$,J,1)= CHR$(45) THEN 2630 2610 IF MID$(I$,J,1)>CHR$(47) AND MID$(I$,J,1)<CHR$(58) THEN 2630 2620 PRINT CHR$(7):GOSUB 10120:GOTO 2460 2630 NEXT J2640 F3=VAL(I$)2650 IF F3<1 OR F3>99 THEN 26202660 COLOR 14,12670 LOCATE 8,13,1:PRINT USING"## \ \";F3,CROP$(F3)2680 COLOR 15,12690 LOCATE 22,1:PRINT " "2700 F3$=" "2710 RSET F3$=STR$(F3)2720 F3$=MID$(F3$,3,2)2730 '2740 ' - Field Number2750 ' - FIELD 4 ALPHA, SIZE A 10 REPEATED WITH 'ENTER'2760 '2770 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";2780 LOCATE 8,37:PRINT MID$(SL$(8),37,32);2790 LOCATE 8, 58,12800 COLOR 14,12810 LINE INPUT I$2820 COLOR 15,12830 IF LEFT$(I$,1)="\" THEN 2460 2840 Z=LEN(I$):IF Z=0 THEN 2870 2850 F4$=" "2860 LSET F4$=I$2870 COLOR 14,12880 LOCATE 8,58,1:PRINT F4$2890 COLOR 15,12900 LOCATE 22,1:PRINT " "2910 '2920 ' - Dry-bulb Temp2930 ' - FIELD 5 DECIMAL, SIZE F 5.1 REPEATED WITH 'ENTER'2940 '2950 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";2960 LOCATE 10,1:PRINT MID$(SL$(10),1,36);2970 LOCATE 10, 32,12980 COLOR 14,12990 LINE INPUT I$3000 COLOR 15,13010 IF LEFT$(I$,1)="\" THEN 2730 3020 Z=LEN(I$):IF Z=0 THEN 3100 3030 Z=LEN(I$)3040 FOR J=1 TO Z3050 IF MID$(I$,J,1)= CHR$(45) OR MID$(I$,J,1)=CHR$(46) THEN 3080 3060 IF MID$(I$,J,1)>CHR$(47) AND MID$(I$,J,1)<CHR$(58) THEN 3080 3070 PRINT CHR$(7):GOSUB 10120:GOTO 2910 3080 NEXT J3090 F5=VAL(I$)3100 IF F5<2 OR F5>54 THEN 30703110 COLOR 14,13120 LOCATE 10,32,1:PRINT USING"###.#";F53130 COLOR 15,13140 LOCATE 22,1:PRINT " "3150 F5$=" "3160 RSET F5$=STR$(F5*10)3170 '


E-7

3180 ' - Wet-bulb Temp3190 ' - FIELD 6 DECIMAL, SIZE F 5.1 REPEATED WITH 'ENTER'3200 '3210 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";3220 LOCATE 10,37:PRINT MID$(SL$(10),37,38);3230 LOCATE 10, 70,13240 COLOR 14,13250 LINE INPUT I$3260 COLOR 15,13270 IF LEFT$(I$,1)="\" THEN 2910 3280 Z=LEN(I$):IF Z=0 THEN 3360 3290 Z=LEN(I$)3300 FOR J=1 TO Z3310 IF MID$(I$,J,1)= CHR$(45) OR MID$(I$,J,1)=CHR$(46) THEN 3340 3320 IF MID$(I$,J,1)>CHR$(47) AND MID$(I$,J,1)<CHR$(58) THEN 3340 3330 PRINT CHR$(7):GOSUB 10120:GOTO 3170 3340 NEXT J3350 F6=VAL(I$)3360 IF F6<2 OR F6>54 THEN 33303370 COLOR 14,13380 LOCATE 10,70,1:PRINT USING"###.#";F63390 COLOR 15,13400 LOCATE 22,1:PRINT " "3410 F6$=" "3420 RSET F6$=STR$(F6*10)3430 '3440 ' - Temp 13450 ' - FIELD 7 DECIMAL, SIZE F 5.1 REPEATED WITH 'ENTER'3460 '3470 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";3480 LOCATE 13,1:PRINT MID$(SL$(13),1,19);3490 LOCATE 13, 15,13500 COLOR 14,13510 LINE INPUT I$3520 COLOR 15,13530 IF LEFT$(I$,1)="\" THEN 3170 3540 Z=LEN(I$):IF Z=0 THEN 3620 3550 Z=LEN(I$)3560 FOR J=1 TO Z3570 IF MID$(I$,J,1)= CHR$(45) OR MID$(I$,J,1)=CHR$(46) THEN 3600 3580 IF MID$(I$,J,1)>CHR$(47) AND MID$(I$,J,1)<CHR$(58) THEN 3600 3590 PRINT CHR$(7):GOSUB 10120:GOTO 3430 3600 NEXT J3610 F7=VAL(I$)3620 IF F7<2 OR F7>54 THEN 35903630 COLOR 14,13640 LOCATE 13,15,1:PRINT USING"###.#";F73650 COLOR 15,13660 LOCATE 22,1:PRINT " "3670 F7$=" "3680 RSET F7$=STR$(F7*10)3690 '3700 ' - Temp 23710 ' - FIELD 8 DECIMAL, SIZE F 5.1 REPEATED WITH 'ENTER'3720 '3730 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";3740 LOCATE 13,20:PRINT MID$(SL$(13),20,15);3750 LOCATE 13, 30,13760 COLOR 14,13770 LINE INPUT I$3780 COLOR 15,13790 IF LEFT$(I$,1)="\" THEN 3430 3800 Z=LEN(I$):IF Z=0 THEN 3880 3810 Z=LEN(I$)3820 FOR J=1 TO Z


E-8

3830 IF MID$(I$,J,1)= CHR$(45) OR MID$(I$,J,1)=CHR$(46) THEN 3860 3840 IF MID$(I$,J,1)>CHR$(47) AND MID$(I$,J,1)<CHR$(58) THEN 3860 3850 PRINT CHR$(7):GOSUB 10120:GOTO 3690 3860 NEXT J3870 F8=VAL(I$)3880 IF F8<2 OR F8>54 THEN 38503890 COLOR 14,13900 LOCATE 13,30,1:PRINT USING"###.#";F83910 COLOR 15,13920 LOCATE 22,1:PRINT " "3930 F8$=" "3940 RSET F8$=STR$(F8*10)3950 '3960 ' - Temp 33970 ' - FIELD 9 DECIMAL, SIZE F 5.1 REPEATED WITH 'ENTER'3980 '3990 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";4000 LOCATE 13,35:PRINT MID$(SL$(13),35,15);4010 LOCATE 13, 45,14020 COLOR 14,14030 LINE INPUT I$4040 COLOR 15,14050 IF LEFT$(I$,1)="\" THEN 3690 4060 Z=LEN(I$):IF Z=0 THEN 4140 4070 Z=LEN(I$)4080 FOR J=1 TO Z4090 IF MID$(I$,J,1)= CHR$(45) OR MID$(I$,J,1)=CHR$(46) THEN 4120 4100 IF MID$(I$,J,1)>CHR$(47) AND MID$(I$,J,1)<CHR$(58) THEN 4120 4110 PRINT CHR$(7):GOSUB 10120:GOTO 3950 4120 NEXT J4130 F9=VAL(I$)4140 IF F9<2 OR F9>54 THEN 41104150 COLOR 14,14160 LOCATE 13,45,1:PRINT USING"###.#";F94170 COLOR 15,14180 LOCATE 22,1:PRINT " "4190 F9$=" "4200 RSET F9$=STR$(F9*10)4210 '4220 ' - Temp 44230 ' - FIELD 10 DECIMAL, SIZE F 5.1 REPEATED WITH 'ENTER'4240 '4250 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";4260 LOCATE 13,50:PRINT MID$(SL$(13),50,15);4270 LOCATE 13, 60,14280 COLOR 14,14290 LINE INPUT I$4300 COLOR 15,14310 IF LEFT$(I$,1)="\" THEN 3950 4320 Z=LEN(I$):IF Z=0 THEN 4400 4330 Z=LEN(I$)4340 FOR J=1 TO Z4350 IF MID$(I$,J,1)= CHR$(45) OR MID$(I$,J,1)=CHR$(46) THEN 4380 4360 IF MID$(I$,J,1)>CHR$(47) AND MID$(I$,J,1)<CHR$(58) THEN 4380 4370 PRINT CHR$(7):GOSUB 10120:GOTO 4210 4380 NEXT J4390 F10=VAL(I$)4400 IF F10<2 OR F10>54 THEN 43704410 COLOR 14,14420 LOCATE 13,60,1:PRINT USING"###.#";F104430 COLOR 15,14440 LOCATE 22,1:PRINT " "4450 F10$=" "4460 RSET F10$=STR$(F10*10)4470 '


E-9

4480 ' - Temp 54490 ' - FIELD 11 DECIMAL, SIZE F 5.1 REPEATED WITH 'ENTER'4500 '4510 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";4520 LOCATE 14,1:PRINT MID$(SL$(14),1,19);4530 LOCATE 14, 15,14540 COLOR 14,14550 LINE INPUT I$4560 COLOR 15,14570 IF LEFT$(I$,1)="\" THEN 4210 4580 Z=LEN(I$):IF Z=0 THEN 4660 4590 Z=LEN(I$)4600 FOR J=1 TO Z4610 IF MID$(I$,J,1)= CHR$(45) OR MID$(I$,J,1)=CHR$(46) THEN 4640 4620 IF MID$(I$,J,1)>CHR$(47) AND MID$(I$,J,1)<CHR$(58) THEN 4640 4630 PRINT CHR$(7):GOSUB 10120:GOTO 4470 4640 NEXT J4650 F11=VAL(I$)4660 IF F11<2 OR F11>54 THEN 46304670 COLOR 14,14680 LOCATE 14,15,1:PRINT USING"###.#";F114690 COLOR 15,14700 LOCATE 22,1:PRINT " "4710 F11$=" "4720 RSET F11$=STR$(F11*10)4730 '4740 ' - Temp 64750 ' - FIELD 12 DECIMAL, SIZE F 5.1 REPEATED WITH 'ENTER'4760 '4770 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";4780 LOCATE 14,20:PRINT MID$(SL$(14),20,15);4790 LOCATE 14, 30,14800 COLOR 14,14810 LINE INPUT I$4820 COLOR 15,14830 IF LEFT$(I$,1)="\" THEN 4470 4840 Z=LEN(I$):IF Z=0 THEN 4920 4850 Z=LEN(I$)4860 FOR J=1 TO Z4870 IF MID$(I$,J,1)= CHR$(45) OR MID$(I$,J,1)=CHR$(46) THEN 4900 4880 IF MID$(I$,J,1)>CHR$(47) AND MID$(I$,J,1)<CHR$(58) THEN 4900 4890 PRINT CHR$(7):GOSUB 10120:GOTO 4730 4900 NEXT J4910 F12=VAL(I$)4920 IF F12<2 OR F12>54 THEN 48904930 COLOR 14,14940 LOCATE 14,30,1:PRINT USING"###.#";F124950 COLOR 15,14960 LOCATE 22,1:PRINT " "4970 F12$=" "4980 RSET F12$=STR$(F12*10)4990 '5000 ' - Temp 75010 ' - FIELD 13 DECIMAL, SIZE F 5.1 REPEATED WITH 'ENTER'5020 '5030 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";5040 LOCATE 14,35:PRINT MID$(SL$(14),35,15);5050 LOCATE 14, 45,15060 COLOR 14,15070 LINE INPUT I$5080 COLOR 15,15090 IF LEFT$(I$,1)="\" THEN 4730 5100 Z=LEN(I$):IF Z=0 THEN 5180 5110 Z=LEN(I$)5120 FOR J=1 TO Z


E-10

5130 IF MID$(I$,J,1)= CHR$(45) OR MID$(I$,J,1)=CHR$(46) THEN 5160 5140 IF MID$(I$,J,1)>CHR$(47) AND MID$(I$,J,1)<CHR$(58) THEN 5160 5150 PRINT CHR$(7):GOSUB 10120:GOTO 4990 5160 NEXT J5170 F13=VAL(I$)5180 IF F13<2 OR F13>54 THEN 51505190 COLOR 14,15200 LOCATE 14,45,1:PRINT USING"###.#";F135210 COLOR 15,15220 LOCATE 22,1:PRINT " "5230 F13$=" "5240 RSET F13$=STR$(F13*10)5250 '5260 ' - Temp 85270 ' - FIELD 14 DECIMAL, SIZE F 5.1 REPEATED WITH 'ENTER'5280 '5290 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";5300 LOCATE 14,50:PRINT MID$(SL$(14),50,15);5310 LOCATE 14, 60,15320 COLOR 14,15330 LINE INPUT I$5340 COLOR 15,15350 IF LEFT$(I$,1)="\" THEN 4990 5360 Z=LEN(I$):IF Z=0 THEN 5440 5370 Z=LEN(I$)5380 FOR J=1 TO Z5390 IF MID$(I$,J,1)= CHR$(45) OR MID$(I$,J,1)=CHR$(46) THEN 5420 5400 IF MID$(I$,J,1)>CHR$(47) AND MID$(I$,J,1)<CHR$(58) THEN 5420 5410 PRINT CHR$(7):GOSUB 10120:GOTO 5250 5420 NEXT J5430 F14=VAL(I$)5440 IF F14<2 OR F14>54 THEN 54105450 COLOR 14,15460 LOCATE 14,60,1:PRINT USING"###.#";F145470 COLOR 15,15480 LOCATE 22,1:PRINT " "5490 F14$=" "5500 RSET F14$=STR$(F14*10)5510 '5520 ' - Wind Speed5530 ' - FIELD 15 INTEGER, SIZE I 2 REPEATED WITH 'ENTER'5540 '5550 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";5560 LOCATE 16,1:PRINT MID$(SL$(16),1,15);5570 LOCATE 16, 14,15580 COLOR 14,15590 LINE INPUT I$5600 COLOR 15,15610 IF LEFT$(I$,1)="\" THEN 5250 5620 Z=LEN(I$):IF Z=0 THEN 5700 5630 Z=LEN(I$)5640 FOR J=1 TO Z5650 IF MID$(I$,J,1)= CHR$(45) THEN 5680 5660 IF MID$(I$,J,1)>CHR$(47) AND MID$(I$,J,1)<CHR$(58) THEN 5680 5670 PRINT CHR$(7):GOSUB 10120:GOTO 5510 5680 NEXT J5690 F15=VAL(I$)5700 IF F15<0 OR F15>99 THEN 56705710 COLOR 14,15720 LOCATE 16,14,1:PRINT USING"##";F155730 COLOR 15,15740 LOCATE 22,1:PRINT " "5750 F15$=" "5760 RSET F15$=MID$(STR$(F15),2,2)5770 '


E-11

5780 ' - Wind Direction5790 ' - FIELD 16 ALPHA, SIZE A 3 REPEATED WITH 'ENTER'5800 '5810 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";5820 LOCATE 16,16:PRINT MID$(SL$(16),16,43);5830 LOCATE 16, 56,15840 COLOR 14,15850 LINE INPUT I$5860 COLOR 15,15870 IF LEFT$(I$,1)="\" THEN 5510 5880 Z=LEN(I$):IF Z=0 THEN 5910 5890 F16$=" "5900 MID$(F16$,1, 3 )=I$5910 FOR I=1 TO 165920 IF F16$=VALID$(I) THEN 59605930 NEXT I5940 PRINT CHR$(7):GOSUB 101205950 GOTO 57705960 COLOR 14,15970 LOCATE 16,56,1:PRINT MID$(F16$,1,3)5980 COLOR 15,15990 LOCATE 22,1:PRINT " "6000 '6010 ' - Slope6020 ' - FIELD 17 DECIMAL, SIZE F 5.1 REPEATED WITH 'ENTER'6030 '6040 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";6050 LOCATE 18,1:PRINT MID$(SL$(18),1,13);6060 LOCATE 18, 9,16070 COLOR 14,16080 LINE INPUT I$6090 COLOR 15,16100 IF LEFT$(I$,1)="\" THEN 5770 6110 Z=LEN(I$):IF Z=0 THEN 6190 6120 Z=LEN(I$)6130 FOR J=1 TO Z6140 IF MID$(I$,J,1)= CHR$(45) OR MID$(I$,J,1)=CHR$(46) THEN 6170 6150 IF MID$(I$,J,1)>CHR$(47) AND MID$(I$,J,1)<CHR$(58) THEN 6170 6160 PRINT CHR$(7):GOSUB 10120:GOTO 6000 6170 NEXT J6180 F17=VAL(I$)6190 COLOR 14,16200 LOCATE 18,9,1:PRINT USING"##.##";F176210 COLOR 15,16220 LOCATE 22,1:PRINT " "6230 F17$=STR$(F17*100)6240 '6250 ' - Offset6260 ' - FIELD 18 DECIMAL, SIZE F 5.1 REPEATED WITH 'ENTER'6270 '6280 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";6290 LOCATE 18,14:PRINT MID$(SL$(18),14,39);6300 LOCATE 18, 48,16310 COLOR 14,16320 LINE INPUT I$6330 COLOR 15,16340 IF LEFT$(I$,1)="\" THEN 6000 6350 Z=LEN(I$):IF Z=0 THEN 6430 6360 Z=LEN(I$)6370 FOR J=1 TO Z6380 IF MID$(I$,J,1)= CHR$(45) OR MID$(I$,J,1)=CHR$(46) THEN 6410 6390 IF MID$(I$,J,1)>CHR$(47) AND MID$(I$,J,1)<CHR$(58) THEN 6410 6400 PRINT CHR$(7):GOSUB 10120:GOTO 6240 6410 NEXT J6420 F18=VAL(I$)


E-12

6430 COLOR 14,16440 LOCATE 18,48,1:PRINT USING"##.##";F186450 COLOR 15,16460 LOCATE 22,1:PRINT " "6470 F18$=STR$(F18*100)6480 '6490 ' - Data Quality Code6500 ' - FIELD 19 INTEGER, SIZE I 2 REPEATED WITH 'ENTER'6510 '6520 LOCATE 23,1:PRINT "ENTER '\' TO BACKSPACE ONE FIELD ";6530 LOCATE 20,1:PRINT MID$(SL$(20),1,47);6540 LOCATE 20, 46,16550 COLOR 14,16560 LINE INPUT I$6570 COLOR 15,16580 IF LEFT$(I$,1)="\" THEN 6240 6590 Z=LEN(I$):IF Z=0 THEN 6670 6600 Z=LEN(I$)6610 FOR J=1 TO Z6620 IF MID$(I$,J,1)= CHR$(45) THEN 6650 6630 IF MID$(I$,J,1)>CHR$(47) AND MID$(I$,J,1)<CHR$(58) THEN 6650 6640 PRINT CHR$(7):GOSUB 10120:GOTO 6480 6650 NEXT J6660 F19=VAL(I$)6670 IF F19<1 OR F19>3 THEN 66406680 COLOR 14,16690 LOCATE 20,46,1:PRINT USING"##";F196700 COLOR 15,16710 LOCATE 22,1:PRINT " "6720 F19$=STR$(F19)6730 LOCATE 23,1,16740 PRINT" "6750 DL$(K)=F1$+F2$+F3$+F4$+F5$+F6$+F7$+F8$+F9$+F10$+F11$+F12$+F13$+F14$6760 DL$(K)=DL$(K)+F15$+F16$+F17$+F18$+F19$6761 K=K+16770 RETURN6780 '6790 '----- SUBROUTINE TO DISPLAY DATA FOR CORRECTION6800 '6810 COLOR 7,16820 F1$=MID$(DL$(K),1,7)6830 LOCATE 4,36,1:PRINT USING"\ \";F1$6840 F2=VAL(MID$(DL$(K),9,4))6850 LOCATE 6,49,1:PRINT USING"####";F26860 F3=VAL(MID$(DL$(K),13,2))6870 LOCATE 8,13,1:PRINT USING"## \ \";F3,CROP$(F3)6880 F4$=MID$(DL$(K),15,10)6890 LOCATE 8,58,1:PRINT F4$6900 F5=VAL(MID$(DL$(K),25,4))/106910 LOCATE 10,32,1:PRINT USING"###.#";F56920 F6=VAL(MID$(DL$(K),29,4))/106930 LOCATE 10,70,1:PRINT USING"###.#";F66940 F7=VAL(MID$(DL$(K),33,4))/106950 LOCATE 13,15,1:PRINT USING"###.#";F76960 F8=VAL(MID$(DL$(K),37,4))/106970 LOCATE 13,30,1:PRINT USING"###.#";F86980 F9=VAL(MID$(DL$(K),41,4))/106990 LOCATE 13,45,1:PRINT USING"###.#";F97000 F10=VAL(MID$(DL$(K),45,4))/107010 LOCATE 13,60,1:PRINT USING"###.#";F107020 F11=VAL(MID$(DL$(K),49,4))/107030 LOCATE 14,15,1:PRINT USING"###.#";F117040 F12=VAL(MID$(DL$(K),53,4))/107050 LOCATE 14,30,1:PRINT USING"###.#";F127060 F13=VAL(MID$(DL$(K),57,4))/10


E-13

7070 LOCATE 14,45,1:PRINT USING"###.#";F137080 F14=VAL(MID$(DL$(K),61,4))/107090 LOCATE 14,60,1:PRINT USING"###.#";F147100 F15=VAL(MID$(DL$(K),65,2))7110 LOCATE 16,14,1:PRINT USING"##";F157120 F16$=MID$(DL$(K),67,3)7130 LOCATE 16,56,1:PRINT F16$7140 F17=VAL(MID$(DL$(K),70,4))/1007150 LOCATE 18,9,1:PRINT USING"##.##";F177160 F18=VAL(MID$(DL$(K),74,4))/1007170 LOCATE 18,48,1:PRINT USING"##.##";F187180 F19=VAL(MID$(DL$(K),78,2))7190 LOCATE 20,46,1:PRINT USING"##";F197200 COLOR 15,17210 RETURN7220 '7230 ' SUBROUTINE TO COMPUTE CWSI7240 '7250 DIM TEMP(8),X(100),Y(100),YC(100), QUAL$(3)7260 QUAL$(1)="GOOD"7270 QUAL$(2)="FAIR"7280 QUAL$(3)="POOR" 7290 OPEN "I",2,D$7300 OPEN "O",3,"OUTPUT"7310 E=2.7182818# 7320 NO=07330 IPAGE=0 7340 IF EOF(2) THEN 87507350 LINE INPUT#2,B$7360 IDATE=VAL(MID$(B$,1,7))7370 IHOUR=VAL(MID$(B$,9,4))7380 ICROP=VAL(MID$(B$,13,2))7390 IFIELD$=MID$(B$,15,10)7400 TA=VAL(MID$(B$,25,4))/107410 TWB=VAL(MID$(B$,29,4))/107420 FOR I=1 TO 87430 M=33+(I-1)*47440 TEMP(I)=VAL(MID$(B$,M,4))/107450 NEXT I7460 WINDS$=MID$(B$,65,2)7470 WINDD$=MID$(B$,67,3)7480 SLOPE=VAL(MID$(B$,70,4))/1007490 OFFSET=VAL(MID$(B$,74,4))/1007500 IQUAL=VAL(MID$(B$,78,2))7510 '7520 ' CHECK FOR BAD DATA7530 ' 7540 IF IQUAL=0 THEN 7550 LPRINT " *****ERROR: BAD DATA QUALITY ON THE FOLLOWING RECORD. ";7560 LPRINT "MUST BE 1, 2 OR 3"7570 LPRINT DATE;IHOUR;ICROP;IFIELD$;TA;TWB;TEMP;WINDS$;WINDD$;SLOPE;OFFSET;IQUAL7580 GOTO 73407590 END IF7600 ' 7610 ' CALCULATE MEAN TEMPERATURE OF PLANT 7620 ' 7630 TMPAVG=(TEMP(1)+TEMP(2)+TEMP(3)+TEMP(4)+TEMP(5)+TEMP(6)+TEMP(7)+TEMP(8))7640 TMPAVG=TMPAVG/8!7650 '7660 ' CALCULATE TEMPERATURE DIFFERENTIAL7670 ' TEMP DIFF = TEMP AVG. - DRY BULB TEMP.7680 ' 7690 TMPDIF = TMPAVG-TA7700 ' 7710 ' CALCULATE THE SATURATION VAPOR PRESSURE


E-14

7720 ' 7730 XP=18.7209-(3806.41/(TA+273.16))-(222153!/(TA+273.16)^2)7740 EO1=E^XP7750 XP=18.7209-(3806.41/(TWB+273.16))-(222153!/(TWB+273.16)^2) 7760 EO2=E^XP 7770 EA=EO2-((.00066*(.00115*TWB+1!))*(980!*(TA-TWB)))7780 VPD1=(EO1-EA)/10!7790 IF (SLOPE=0! AND OFFSET=0!) THEN7800 '7810 ' DEVELOPING THE REGRESSION EQUATION. STORE VPD AND TC-TA VALUE7820 ' 7830 PRINT7840 PRINT DL$(K)7850 PRINT "Record skipped, no slope of offset provided."7860 GOTO 7340 7870 END IF7880 '7890 ' NOW CALCULATE THE UPPER LIMIT.7900 ' 7910 TC=TA+OFFSET7920 XP=18.7209-(3806.41/(TC+273.16))-(222153!/(TC+273.16)^2) 7930 VPD2=E^XP7940 VPDIFF=(EO1-VPD2)/10!7950 UPLMT=OFFSET+(SLOPE*VPDIFF) 7960 ' 7970 ' CALCULATE THE CROP WATER STRESS INDEX 7980 ' 7990 CWSI=(TMPDIF-(SLOPE*VPD1+OFFSET))/(UPLMT-(SLOPE*VPD1+OFFSET)) 8000 ' 8010 ' CALCULATE RELATIVE HUMIDITY 8020 ' 8030 RH=EA/EO1*100! 8040 ' 8050 ' ALL DONE WITH THIS SAMPLE. PRINT ANSWERS 8060 ' 8070 NO=NO+1 8080 IF NO=0 GOTO 8290 '------LOOKS FOR BLANK DATE?8090 '8100 ' WRITE HEADINGS. 8110 ' 8120 IF NP=1 THEN 8130 ELSE 82308130 IPAGE= IPAGE + 18140 LPRINT CHR$(12);TAB(22);"CROP WATER STRESS INDEX COMPUTATIONS"8150 D$=DATE$8160 TODAY$=MID$(D$,1,2)+"/"+MID$(D$,4,2)+"/"+MID$(D$,9,2)8170 LPRINT TAB(36);TODAY$8180 LPRINT TAB(37);"Page ";IPAGE8190 LPRINT8200 LPRINT8210 NP=28220 GOTO 82808230 LPRINT8240 LPRINT TAB(30);"- - - - - - - - - -"8250 LPRINT8260 LPRINT8270 NP=18280 NO=18290 LPRINT TAB(7);"SAMPLE";TAB(17);"SAMPLE"8300 LPRINT TAB(8);"DATE";TAB(18);"TIME";TAB(28);"CROP";TAB(44);"FIELD"8310 LPRINT TAB(7);"------";TAB(17);"------";TAB(28);"----";TAB(44);"-----"8320 MO=INT(IDATE/10000)8330 DY=INT(IDATE/100)-MO*1008340 YR=IDATE-DY*100-MO*100008350 LPRINT USING" ##/##/## ######";MO,DY,YR,IHOUR;8360 LPRINT USING" \ \ \ \";CROP$(ICROP),IFIELD$


E-15

8370 LPRINT8380 LPRINT " DRY BULB";TAB(13);"WET BULB";TAB(36);"SAMPLE TEMPERATURES";8390 LPRINT TAB(75);"DATA"8400 LPRINT TAB(5);"TEMP";TAB(15);"TEMP";8410 LPRINT TAB(24);"(1) (2) (3) (4) (5) (6) (7) (8) WIND";8420 LPRINT TAB(73);"QUALITY"8430 LPRINT " --------";TAB(13);"--------";TAB(24);8440 LPRINT "---- ---- ---- ---- ---- ---- ---- ---- ----";8450 LPRINT TAB(73);"-------" 8460 LPRINT USING" ##.# ##.# ";TA,TWB;8470 LPRINT USING" ##.# ##.# ##.# ##.#";TEMP(1),TEMP(2),TEMP(3),TEMP(4);8480 LPRINT USING" ##.# ##.# ##.# ##.#";TEMP(5),TEMP(6),TEMP(7),TEMP(8);8490 LPRINT USING" \\ \ \ \ \";WINDS$,WINDD$,QUAL$(IQUAL)8500 LPRINT8510 LPRINT " SLOPE: ";8520 LPRINT USING" #####.##";SLOPE8530 LPRINT8540 LPRINT " OFFSET: ";8550 LPRINT USING" #####.##";OFFSET8560 LPRINT8570 LPRINT " TC-TA ";8580 LPRINT USING" #####.## C";TMPDIF8590 LPRINT8600 LPRINT " VAPOR PRESSURE DEFICIT: ";8610 LPRINT USING" #####.## KPA";VPD18620 LPRINT8630 LPRINT " UPPER LIMIT: ";8640 LPRINT USING" #####.## C";UPLMT8650 LPRINT8660 LPRINT " CROP WATER STRESS INDEX: ";8670 LPRINT USING" #####.##";CWSI8680 LPRINT8690 LPRINT " RELATIVE HUMIDITY: ";8700 LPRINT USING" #####.##%";RH8710 GOTO 73408720 ' 8730 ' END OF FILE.8740 ' 8750 RETURN8760 '8770 ' SUBROUTINE TO COMPUTE SLOPE AND OFFSET8780 '8790 E=2.7182818# 8800 NO=08810 IPAGE=0 8820 XCROP=08830 IF EOF(2) THEN 92508840 NO=NO+18850 LINE INPUT#2,B$8860 ICROP=VAL(MID$(B$,13,2))8870 'PRINT XCROP,ICROP8880 IF XCROP=0 OR XCROP=ICROP THEN 89308890 LPRINT B$8900 LPRINT "DATA SKIPPED, CROP NOT ";CROP$(XCROP)8910 NO=NO-18920 GOTO 88308930 XCROP=ICROP8940 TA=VAL(MID$(B$,25,4))/108950 TWB=VAL(MID$(B$,29,4))/108960 FOR I=1 TO 88970 M=33+(I-1)*48980 TEMP(I)=VAL(MID$(B$,M,4))/108990 NEXT I9000 ' 9010 ' CALCULATE MEAN TEMPERATURE OF PLANT


E-16

9020 ' 9030 TMPAVG=(TEMP(1)+TEMP(2)+TEMP(3)+TEMP(4)+TEMP(5)+TEMP(6)+TEMP(7)+TEMP(8))9040 TMPAVG=TMPAVG/8!9050 '9060 ' CALCULATE TEMPERATURE DIFFERENTIAL9070 ' TEMP DIFF = TEMP AVG. - DRY BULB TEMP.9080 ' 9090 TMPDIF = TMPAVG-TA9100 ' 9110 ' CALCULATE THE SATURATION VAPOR PRESSURE 9120 ' 9130 XP=18.7209-(3806.41/(TA+273.16))-(222153!/(TA+273.16)^2)9140 EO1=E^XP9150 XP=18.7209-(3806.41/(TWB+273.16))-(222153!/(TWB+273.16)^2) 9160 EO2=E^XP 9170 EA=EO2-((.00066*(.00115*TWB+1!))*(980!*(TA-TWB)))9180 VPD1=(EO1-EA)/10!9190 X(NO)=VPD1 9200 Y(NO)=TMPDIF 9210 ISW=1 9220 JCROP$=CROP$(ICROP) 9230 GOTO 8830 9240 ' CALCUALTE SLOPE AND OFFSET9250 XSUM=0!9260 X2SUM=0! 9270 YSUM=0!9280 XYSUM=0! 9290 Y2SUM=0! 9300 '9310 ' SUM UP THE X VALUES 9320 ' 9330 FOR J=1 TO NO9340 XSUM=XSUM+X(J)9350 NEXT J9360 '9370 ' SUM UP X SQUARED VALUES 9380 ' 9390 FOR J=1 TO NO9400 X2SUM=X2SUM + X(J)^2 9410 NEXT J9420 '9430 ' SUM UP THE Y VALUES 9440 ' 9450 FOR J=1 TO NO9460 YSUM=YSUM+Y(J)9470 NEXT J9480 '9490 ' SUM THE PRODUCT OF X*Y9500 ' 9510 FOR J=1 TO NO9520 XYSUM=XYSUM+(X(J)*Y(J)) 9530 NEXT J9540 '9550 ' SUM UP THEE Y SQUARED VALUES9560 ' 9570 FOR J=1 TO NO9580 Y2SUM=Y2SUM + Y(J)^2 9590 NEXT J9600 '9610 ' DETERMINE THE ARITHMETIC MEAN FOR X AND Y 9620 ' 9630 XMEAN=XSUM/NO9640 YMEAN=YSUM/NO9650 '9660 ' COMPUTE THE M(11),M(12), AND M(22) VALUES


E-17

9670 ' 9680 M11=Y2SUM-(NO*(YMEAN)^2)9690 M12=XYSUM-(NO*YMEAN*XMEAN) 9700 M22=X2SUM-(NO*(XMEAN^2))9710 '9720 ' NOW THE 'B' AND 'A' VALUES9730 ' 9740 B=M12/M22 9750 A=YMEAN-B*XMEAN 9760 SLOPE=B 9770 OFFSET=A9780 ' 9790 ' NOW CALCULATE THE R SQUARED VALUE AND WE ARE DONE.9800 ' 9810 SST=M11 9820 SSR=ABS(B)^2*M22 9830 R2=SSR/SST9840 'IF ISW=0 THEN 6560 9850 LPRINT CHR$(12);TAB(26);"SLOPE AND OFFSET CALCULATIONS"9860 LPRINT9870 LPRINT9880 LPRINT USING" VPD AND TC-TA DATA PAIRS FOR WELL-WATERED \ \";CROP$(XCROP)9890 LPRINT9900 LPRINT TAB(21);"TC-TA TC-TA"9910 LPRINT " POINT VPD (ACTUAL) (CALC)"9920 LPRINT9930 FOR J=1 TO NO9940 YC(J)=SLOPE*X(J)+OFFSET 9950 LPRINT USING" ### ####.# ####.# ####.# ####.#";J,X(J),Y(J),YC(J)9960 NEXT J9970 LPRINT9980 LPRINT USING" REGRESSION EQUATION: #####.## + #####.## X";OFFSET,SLOPE9990 LPRINT USING" R SQUARED= ###.##";R210000 LPRINT CHR$(12)10010 RETURN10020 '10030 ' SUBROUTINE TO PRINT DATA FILE10040 '10050 OPEN "O",1,D$10060 FOR I=1 TO 5010070 IF MID$(DL$(I),1,7)<=" " THEN 1010010080 PRINT#1,DL$(I)10090 NEXT I10100 CLOSE10110 RETURN10120 '10130 ' SUBROUTINE TO DISPLAY BAD DATA MESSAGE10140 '10150 COLOR 12,110160 LOCATE 22,1,110170 PRINT "BAD DATA, TRY AGAIN. "10180 COLOR 15,110190 RETURN10200 '10201 ' SUBROUTINE TO SORT DATA BY FIELD NUMBER AND SAMPLING DATE10202 '10210 ' Build Sort Key10220 '10230 X2$ = ""10231 'NR=K10232 'LPRINT NR,CHR$(12)10240 For L = 1 To NR10242 X2$=MID$(DL$(L),15,10)


E-18

10244 X2$=X2$+MID$(DL$(L),6,2)10246 X2$=X2$+MID$(DL$(L),2,2)10248 X2$=X2$+MID$(DL$(L),4,2)10250 X2$=X2$+MID$(DL$(L),9,4)10460 '10470 ' Locate Record Position in File10480 '10490 If L = 1 Then10500 RPointer(L) = L10510 skey$(L) = X2$10520 NumRec = L10530 GoTo 11330 'loop310540 End If10550 LL = 110560 UL = NumRec10570 If X2$ < skey$(LL) Then10580 'Print #F2, X2$; "<"; skey(LL), LL10590 RN = 110600 GoTo 11150 'InsertRcd10610 End If10620 If X2$ = skey$(LL) Then16030 'Print #F2, X2$; "="; skey(LL), LL10640 RN = LL10650 'Loop1:10660 RN = RN + 116070 If RN > NumRec Then16080 RN = NumRec10690 GoTo 11290 'AppendRecord10700 End If10710 If X2$ = skey$(RN) Then10720 GoTo 10650 'Loop110730 Else10740 RN = RN - 110750 If RN <= 0 Then RN = 110760 GoTo 11150 'InsertRcd10770 End If10780 End If10790 If X2$ > skey$(UL) Then10800 'Print #F2, X2$; ">"; skey(UL), UL10810 GoTo 11290 'AppendRecord10820 End If10830 If X2$ = skey$(UL) Then10840 'Print #F2, X2$; "="; skey(UL), UL10850 RN = UL10860 'Loop2:10870 RN = RN + 110880 If RN > NumRec Then10890 RN = NumRec10900 GoTo 11290 'AppendRecord10910 End If10920 If X2$ = skey$(RN) Then10930 GoTo 10860 'Loop210940 Else10950 ' RN = RN - 110960 If RN <= 0 Then RN = 110970 GoTo 11150 'InsertRcd10980 End If11000 End If11010 'LBL4091:11020 X = Int((UL + LL) / 2 + .5)11030 'Print #F2, X2$, skey(X), X11040 If X2$ > skey$(X) Then11050 LL = X11060 Else11070 UL = X


E-19

11080 End If11090 'Print #F2, L, LL; X; UL, LLX$; X2$; ULX$11100 If (UL - LL) = 1 Then11110 RN = UL11120 GoTo 11150 'InsertRcd11130 End If11140 GoTo 11010 'LBL409111150 'InsertRcd:11160 For J = NumRec To RN Step -111170 If J <= 0 Then11180 GoTo 11240 'Loop511190 End If11200 'Print #F2, J, NumRec, RN11210 skey$(J + 1) = skey$(J)11220 RPointer(J + 1) = RPointer(J)11230 Next J11240 'Loop5:11250 skey$(RN) = X2$11260 RPointer(RN) = L11270 NumRec = NumRec + 111280 GoTo 11330 'loop311290 'AppendRecord:11300 NumRec = NumRec + 111310 skey$(NumRec) = X2$11320 RPointer(NumRec) = L11330 'loop3:11340 '11350 Next L11560 'Close #F111370 ' All Records sorted, create new file.11430 Open D$ For Output As 111440 'Open FILEIN$ For Random As F1 Len = RL11450 For I = 1 To NR11460 'Print #F3, rpointer(I)11500 Print #1, DL$(RPOINTER(I))11510 Next I11520 Close11580 RETURN

Index

Index-1

INDEXAccess tube

Accessibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13, 23location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31, 32Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31, 37

Access tubes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13, 14, 18, 21, 23, 32Acres . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2, 41Adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1Amount to apply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Apparent Moisture Content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Black body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20, 21Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18, 21, 22, 25, 26, 28Consumptive Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31, 37Crop . . . . . . . . . . . . . . . . . . . . . . . 1, 2, 4, 6, 8-10, 20-23, 30-37, 39, 41, E-1, E-2, E-5, E-6, E-12, E-14-17Crop Name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21, E-1Crop stand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Crop water Stress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6, 9, 10, 20, 33-36, E-1, E-14, E-15Crop Water Stress Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6, 9, 10, 33-36, E-1, E-14, E-15CWSI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10, 20, 30, 33, 35, 36, E-1, E-2, E-4, E-13-15Data Sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22, 33

Plant foliage temperature data sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22, 33Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4, 6, 22, 29, 34-37, 40, 41, E-2, E-5, E-13-15, E-18Dosimeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25DR-503 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14, 15, 18, 26, 28, 35Dry Barrel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19, 26-28Dry-Bulb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20, 21, 36Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1, 4, 6, 33, 37Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Excess water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31, 34Farm irrigation schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41Farm number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Field data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33, C-2Field Irrigation Scheduling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2, 4, 24, 35Film badge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4, 13-15, 18, 19, 21, 24-28, 32, 33, 35, 37, C-1Infrared thermometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10, 13, 19-21, 30, 33Initialize the gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Irrigation Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31License . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12, 21, E-1, E-3, E-4Neutron Moisture Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4, 13, 19, 24, 26, 27, C-1Neutron Probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii-5, 29Next irrigation date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4, 6NRC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24, 25Nuclear Regulatory Commission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Plant foliage temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22, 33Plant foliage temperature data sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22, 33Probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii-5, 14-19, 21, 23, 26, 28, 29, 37Psychrometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10, 20, 21, 30, 33Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Refill Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4, 6, 10, 37Refill point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4, 10, 31-33, 35Run . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1S-503 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14, 15, 26, 28, 35

Index

Index-2

Schedules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2, 37, 39Scheduling irrigations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1, 3, 4, 26, 31Soil Moisture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4, 6, 8, 10, 15, 21, 25-27, 32-34Soil Moisture depletion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Soil Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26, 31Standard count . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15, 18, 29Standardization Barrel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Summary report sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37Technicians . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24, 31, 37, 39Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6, 8-11, 20-22, 30, 33, 36, A-1, A-5, E-2, E-14, E-16Tube location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31, 32Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21, 22, 26, 31, E-1VEGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33, 34, 7, E-1, E-2Visible stress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Water user . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Wet Barrel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19, 26, 28Wet-bulb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 20, A-1, A-2, A-4, A-5

Documents

IRRIGATION SCHEDULING Using REAL TIME SOIL MOISTURE ... › uc › progact › waterconsv › pdfs › IMSReport_Master1.pdfthe LC Region worked with a company that manufactured neutron